私たちは、薬学部（シドニー大学）、エルチェス大学研究基金、TUBITAK（1059B141400496）の財政​​支援を認めています。ビデオを編集してくれたTim Harland（シドニー大学）に感謝します。

<ol>
	<li>Akkoc, S., Gok, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+characterization+of+1-phenyl-3-alkylbenzimidazol-2-ylidene+salts+and+their+catalytic+activities+in+the+Heck+and+Suzuki+cross-coupling+reactions.">Synthesis and characterization of 1-phenyl-3-alkylbenzimidazol-2-ylidene salts and their catalytic activities in the Heck and Suzuki cross-coupling reactions.</a> J. Coord. Chem. 66 (8), 1396-1404 (2013).</li><li>Aktas, A., Akkoc, S., Gok, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Palladium+catalyzed+Mizoroki-Heck+and+Suzuki-Miyaura+reactions+using+naphthalenomethyl-substituted+imidazolidin-2-ylidene+ligands+in+aqueous+media.">Palladium catalyzed Mizoroki-Heck and Suzuki-Miyaura reactions using naphthalenomethyl-substituted imidazolidin-2-ylidene ligands in aqueous media.</a> J. Coord. Chem. 66 (16), 2901-2909 (2013).</li><li>Cetinkaya, B., Alici, B., Ozdemir, I., Bruneau, C., Dixneuf, P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=2-imidazoline+and+1,4,5,6-tetrahydropyrimidine-ruthenium(II)+complexes+and+catalytic+synthesis+of+furan.">2-imidazoline and 1,4,5,6-tetrahydropyrimidine-ruthenium(II) complexes and catalytic synthesis of furan.</a> J. Organomet. Chem. 575 (2), 187-192 (1999).</li><li>Chouthaiwale, P. V., Rawat, V., Sudalai, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pd-catalyzed+selective+hydrosilylation+of+aryl+ketones+and+aldehydes.">Pd-catalyzed selective hydrosilylation of aryl ketones and aldehydes.</a> Tetrahedron Lett. 53 (2), 148-150 (2012).</li><li>Herrmann, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-heterocyclic+carbenes:+A+new+concept+in+organometallic+catalysis.">N-heterocyclic carbenes: A new concept in organometallic catalysis.</a> Angew. Chem. Int. Ed. 41 (8), 1290-1309 (2002).</li><li>Jensen, T. R., Schaller, C. P., Hillmyer, M. A., Tolman, W. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zinc+N-heterocyclic+carbene+complexes+and+their+polymerization+of+D,L-lactide.">Zinc N-heterocyclic carbene complexes and their polymerization of D,L-lactide.</a> J. Organomet. Chem. 690 (24-25), 5881-5891 (2005).</li><li>Lai, Y. B., Lee, C. S., Lin, W. J., Naziruddin, A. R., Hwang, W. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bis-chelate+N-heterocyclic+tetracarbene+Ru(II)+complexes:+Synthesis,+structure,+and+catalytic+activity+toward+transfer+hydrogenation+of+ketones.">Bis-chelate N-heterocyclic tetracarbene Ru(II) complexes: Synthesis, structure, and catalytic activity toward transfer hydrogenation of ketones.</a> Polyhedron. 53, 243-248 (2013).</li><li>Savka, R. D., Plenio, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+hexahydro-s-indacene+based+NHC+ligand+for+olefin+metathesis+catalysts.">A hexahydro-s-indacene based NHC ligand for olefin metathesis catalysts.</a> J. Organomet. Chem. 710, 68-74 (2012).</li><li>Yigit, M., Yigit, B., Gok, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+novel+palladium(II)+N-heterocyclic+carbene+complexes+and+their+catalytic+activities+in+the+direct+C5+arylation+reactions.">Synthesis of novel palladium(II) N-heterocyclic carbene complexes and their catalytic activities in the direct C5 arylation reactions.</a> Inorg. Chim. Acta. 453, 23-28 (2016).</li><li>Yasar, S., Sahin, C., Arslan, M., Ozdemir, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis,+characterization+and+the+Suzuki-Miyaura+coupling+reactions+of+N-heterocyclic+carbene-Pd(II)-pyridine+(PEPPSI)+complexes.">Synthesis, characterization and the Suzuki-Miyaura coupling reactions of N-heterocyclic carbene-Pd(II)-pyridine (PEPPSI) complexes.</a> J. Organomet. Chem. 776, 107-112 (2015).</li><li>Ozdemir, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-Heterocyclic+carbenes:+Useful+ligands+for+the+palladium-catalysed+direct+C5+arylation+of+heteroaromatics+with+aryl+bromides+or+electron-deficient+aryl+chlorides.">N-Heterocyclic carbenes: Useful ligands for the palladium-catalysed direct C5 arylation of heteroaromatics with aryl bromides or electron-deficient aryl chlorides.</a> Eur. J. Inorg. Chem. 12 (12), 1798-1805 (2010).</li><li>Clavier, H., Nolan, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-heterocyclic+carbene+and+phosphine+ruthenium+indenylidene+precatalysts:+A+comparative+study+in+Olefin+metathesis.">N-heterocyclic carbene and phosphine ruthenium indenylidene precatalysts: A comparative study in Olefin metathesis.</a> Chem. Eur. J. 13 (28), 8029-8036 (2007).</li><li>Johnson, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Catalyzed+reactions+of+acyl+anion+equivalents.">Catalyzed reactions of acyl anion equivalents.</a> Angew. Chem. Int. Ed. 43 (11), 1326-1328 (2004).</li><li>Marion, N., Diez-Gonzalez, S., Nolan, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-heterocyclic+carbenes+as+organocatalysts.">N-heterocyclic carbenes as organocatalysts.</a> Angew. Chem. Int. Ed. 46 (17), 2988-3000 (2007).</li><li>Perry, M. C., Burgess, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chiral+N-heterocyclic+carbene-transition+metal+complexes+in+asymmetric+catalysis.">Chiral N-heterocyclic carbene-transition metal complexes in asymmetric catalysis.</a> Tetrahedron: Asymmetry. 14 (8), 951-961 (2003).</li><li>Zeitler, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extending+mechanistic+routes+in+heterazolium+catalysis-promising+concepts+for+versatile+synthetic+methods.">Extending mechanistic routes in heterazolium catalysis-promising concepts for versatile synthetic methods.</a> Angew. Chem. Int. Ed. 44 (46), 7506-7510 (2005).</li><li>Schwarz, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-Heterocyclic+carbenes,+part+25+-+Polymer-supported+carbene+complexes+of+palladium:+Well-defined,+air-stable,+recyclable+catalysts+for+the+Heck+reaction.">N-Heterocyclic carbenes, part 25 - Polymer-supported carbene complexes of palladium: Well-defined, air-stable, recyclable catalysts for the Heck reaction.</a> Chem. Eur. J. 6 (10), 1773-1780 (2000).</li><li>Akkoc, S., Gok, Y., Ilhan, I. O., Kayser, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-Methylphthalimide-substituted+benzimidazolium+salts+and+PEPPSI+Pd-NHC+complexes:+synthesis,+characterization+and+catalytic+activity+in+carbon-carbon+bond-forming+reactions.">N-Methylphthalimide-substituted benzimidazolium salts and PEPPSI Pd-NHC complexes: synthesis, characterization and catalytic activity in carbon-carbon bond-forming reactions.</a> Beilstein J. Org. Chem. 12, 81-88 (2016).</li><li>Karaca, E. O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Palladium+complexes+with+tetrahydropyrimidin-2-ylidene+ligands:+Catalytic+activity+for+the+direct+arylation+of+furan,+thiophene,+and+thiazole+derivatives.">Palladium complexes with tetrahydropyrimidin-2-ylidene ligands: Catalytic activity for the direct arylation of furan, thiophene, and thiazole derivatives.</a> Organometallics. 34 (11), 2487-2493 (2015).</li><li>Ozdemir, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-Heterocyclic+carbene-palladium+catalysts+for+the+direct+arylation+of+pyrrole+derivatives+with+aryl+chlorides.">N-Heterocyclic carbene-palladium catalysts for the direct arylation of pyrrole derivatives with aryl chlorides.</a> Beilstein J. Org. Chem. 9, 303-312 (2013).</li><li>Senocak, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis,+crystal+structures,+magnetic+properties+and+Suzuki+and+Heck+coupling+catalytic+activities+of+new+coordination+polymers+containing+tetracyanopalladate(II)+anions.">Synthesis, crystal structures, magnetic properties and Suzuki and Heck coupling catalytic activities of new coordination polymers containing tetracyanopalladate(II) anions.</a> Polyhedron. 49 (1), 50-60 (2013).</li><li>Akkoc, S., Gok, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dichlorido(3-chloropyridine-N)+1,3-dialkylbenzimidazol-2-ylidene+palladium(II)+complexes:+Synthesis,+characterization+and+catalytic+activity+in+the+arylation+reaction.">Dichlorido(3-chloropyridine-N) 1,3-dialkylbenzimidazol-2-ylidene palladium(II) complexes: Synthesis, characterization and catalytic activity in the arylation reaction.</a> Inorg. Chim. Acta. 429, 34-38 (2015).</li><li>Akkoc, S., Gok, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Catalytic+activities+in+direct+arylation+of+novel+palladium+N-heterocyclic+carbene+complexes.">Catalytic activities in direct arylation of novel palladium N-heterocyclic carbene complexes.</a> Appl. Organomet. Chem. 28 (12), 854-860 (2014).</li><li>Akkoc, S., Gok, Y., Ilhan, I. O., Kayser, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+situ+Generation+of+Efficient+Palladium+N-heterocyclic+Carbene+Catalysts+Using+Benzimidazolium+Salts+for+the+Suzuki-Miyaura+Cross-coupling+Reaction.">In situ Generation of Efficient Palladium N-heterocyclic Carbene Catalysts Using Benzimidazolium Salts for the Suzuki-Miyaura Cross-coupling Reaction.</a> Curr. Org. Synth. 13 (5), 761-766 (2016).</li></ol>

著者は何も開示することはない。

4つのベンズイミダゾリウム塩およびその後のそれらのパラジウムNHC錯体の合成および精製のためのプロトコールは、若い科学者または新しいフィールド科学者がそれらを習得するのを助けるために意図的に詳細に提示された。この同じ目的を念頭に置いて、アリール化および鈴木 - 宮浦反応における4つの錯体の触媒活性を試験するためのプロトコールもまた詳細に提示された。さらに、本発明者らは、多くの他の/新しいパラジウムNHC錯体の触媒活性の合成、精製および試験のために他の人が容易にそれらを適合させることを可能にするために、一般的な形式でプロトコールを提示しようと試みた。 必要に応じて、プロトコルにいくつかの変更が加えられます。可能な変更の提案は、関連する手順の下の議定書のセクションで与えられている。これらの提案のいくつかは、オプションで強調表示されている特定のプロトコルステップの省略についてのものであるが、他はexchaプロトコルの特定のステップで使用される装置または試薬を使用する。試薬の変更に関しては、プロトコールで使用されている試薬の一部を他の試薬と置き換えることは原則として可能ですが、実験的にまたは短時間の測量で確認した例のみに限定して提案しています文献の合成された錯体の触媒活性に関して、アリール化反応の触媒作用に対するそれらの値は、表1の代表的な結果を通して見ることができる.2- n-ブチルフランと4-ブロモアセトフェノンとの間の反応を触媒するために、錯体6が良好な候補であった複合体7および8は特に良好に機能した（表1、項目2〜5）。錯体7は、2 -n-ブチルフランとブロモベンゼンとの反応のための優れた触媒であった（表1、エントリー6-8）。この反応の収率に対する温度の上昇の正の効果は、反応が適切な錯体によって触媒され、温度などの他の反応条件を改変することにより、収率を最大にすることができる。錯体8は2- n-ブチルチオフェンと4-ブロモアニソールとの反応のために触媒として非常に良好に機能するが、2 -n-ブチルチオフェンとブロモベンゼンとの反応のためには優れた触媒であった（表1、エントリー9）表1、エントリー10）。全体として、研究された各アリール化反応は、合成された4つの錯体のうちの少なくとも1つによってうまく触媒された。時間および温度のような反応条件を変更することによって、これらの反応のための収率値を潜在的に増加させるためにさらなる研究を行うことができる。 ボロン酸誘導体と塩化アリールとの間の鈴木 - 宮浦反応の触媒作用のために、合成された錯体は、この研究で使用された反応条件下で可変性能を示した（表2）。複合体5-7は良好な候補であることが判明したが、複合体8は、2,5-ジメトキシフェニルボロン酸と4-メトキシ-1-クロロベンゼンとの間の反応（表2、項目1~4）。すべての4つの錯体は、4-tert-ブチルフェニルボロン酸と4-クロロトルエンとの間の反応のための優れた触媒であった（表2、エントリー5-8）。チアナフテン-2-ボロン酸と1-クロロ-4-ニトロベンゼンとの反応のために、錯体5および6は触媒としては十分に機能しなかったが、錯体7および8はいくつかの有望性を示した（表2、エントリー9-12）。全体として、アリール化反応の結果と同様に、研究されたスズキ - ミヤウラ反応の各々は、合成された4つの錯体の少なくとも1つによって良好に触媒された。選択された複合体が所与の反応を触媒する上で良好に実施された場合、時間、温度、溶媒組成および使用される塩基のような反応条件を変化させることによって転化率および収率値を潜在的に増加させるさらなる作業を行うことができる。 要約すると、4つのパラジウムNHC錯体は、詳細なプロトコールが与えられ、多くの炭素 - 炭素結合形成反応の触媒作用の有望な候補であることが証明された。

特に、メタセシス、フランの生成、重合、ヒドロシリル化、水素化、アリール化、鈴木 - 宮浦クロスカップリングおよびミゾロキ - ヘッククロスカップリングなどの様々な重要な反応を触媒するその能力について、 N-複素環式カルベン（NHC）が注目されている1、2、3、4、5、6、7、8、9、10、11。 NHCは金属と結合することができる。このような金属- NHC錯体が広く、14、13、補助配位子および有機触媒12等の遷移金属触媒反応において使用されています</SUP&gt; 15、16。一般的に、それらは、金属-炭素配位結合17の高い解離エネルギーの結果として空気、水分及び熱に対して非常に安定です。 ここでは、4つのベンゾイミダゾリウム塩（化合物1 - 4）の先に示した合成および精製のためのプロトコルとそのパラジウムNHC錯体（化合物5から 8、それぞれが）18の詳細です。塩および複合体は、種々の技術を用いて以前に特徴付けられた18 。同様の化合物がアリール化と鈴木-宮浦クロスカップリング反応9、10、11の触媒作用のために使用されているので、アリール化及び鈴木-宮浦反応において複合体の触媒活性を試験するためのプロトコルでありますlso詳細。重要なことに、複合体の触媒活性を合成、精製および試験するためのプロトコールは、一般的に、新しいパラジウムNHC複合体への容易な適合を可能にするために提示される。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1-chloro-4-nitrobenzene</td>
			<td>Sigma-Aldrich (Interlab A.S., USA)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>2,5-dimethoxyphenylboronic acid</td>
			<td>Sigma-Aldrich (Interlab A.S., USA)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>2-n-butylfuran</td>
			<td>Sigma-Aldrich (Interlab A.S., USA)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>2-n-butylthiophene</td>
			<td>Sigma-Aldrich (Interlab A.S., USA)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>3-chloropyridine</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4-bromoacetophenone</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4-bromoanisole</td>
			<td>Sigma-Aldrich (Interlab A.S., USA)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4-chlorotoluene</td>
			<td>Sigma-Aldrich (Interlab A.S., USA)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4-methoxy-1-chlorobenzene</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4-tert-butylphenylboronic acid</td>
			<td>Sigma-Aldrich (Interlab A.S., USA)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Benzimidazole</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bromobenzene</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Celite</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dichloromethane</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Diethyl ether</td>
			<td>Sigma-Aldrich (Interlab A.S., USA)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ethyl acetate</td>
			<td>Sigma-Aldrich (Interlab A.S., USA)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ethyl alcohol</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hexane</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Magnesium sulfate</td>
			<td>Scharlau (Barcelona, Spain)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>N,N-dimethylacetamide</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>N,N-dimethylformamide</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Palladium chloride</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Phenylboronic acid</td>
			<td>Sigma-Aldrich (Interlab A.S., USA)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium acetate</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium carbonate</td>
			<td>Scharlau (Barcelona, Spain)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium hydroxide</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Silica gel</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium tert-butoxide</td>
			<td>Merck (Darmstadt, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Thianaphthene-2-boronic acid</td>
			<td>Sigma-Aldrich (Interlab A.S., USA)</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

palladium n-heterocyclic carbene complexes: synthesis from benzimidazolium salts and catalytic activity in carbon-carbon bond-forming reactions

ベンズイミダゾリウム塩からの4つのパラジウムN複素環カルベン錯体の合成およびその後の精製のための詳細で一般化されたプロトコールが提示される。アリール化および鈴木 - 宮浦クロスカップリング反応におけるこのような錯体の触媒活性を試験するための詳細で一般化されたプロトコールもまた提示される。アリール化および鈴木 - 宮浦型反応における4つの錯体の触媒活性についての代表的な結果が示されている。研究された反応の各々について、4つの錯体の少なくとも1つが反応を首尾よく触媒し、それらを多くの炭素 - 炭素結合形成反応の触媒の有望な候補として認定した。示されたプロトコールは、新しいパラジウムN複素環式カルベン錯体の合成、精製および触媒活性試験に適合させるのに十分一般的である。

ベンゾイミダゾリウム塩（1 - 4）18、24の前に報告されているように（ 図1）は次いで、精製し、特徴付けNの -alkylbenzimidazolesと種々のアルキルハライドを用いて、無水DMF中で合成しました。それらは、白色またはクリーム色の固体であり、収率は62％〜97％であった。パラジウムNHC錯体（5から 8）、24 18の前に報告されているように（ 図2）を 、また、精製された塩から合成し、特徴付けました。それらは黄色またはクリーム色の固体であり、塩よりも収率が低く、25％〜60％の範囲であった。 4つのパラジウム錯体を、アリール化および鈴木 - 宮浦クロスカップリング反応における触媒活性について試験した。 n-ブチルチオフェンと4-ブロモアセトフェノン（表1、エントリー1）との間の反応を例として挙げた。この特定の反応は、触媒複合体の非存在下で、110℃で1時間後にわずか1％の収率しか与えなかった。 2- n-ブチルフランと4-ブロモアセトフェノンとの反応のために、錯体5-8は110℃で1時間後にそれぞれ14,49,83および89％の収率をもたらした（表1、項目2~5）。表1の項目6〜8は、錯体7の存在下での2 -n-ブチルフランとブロモベンゼンとの反応を示す。それぞれ80,90および110℃で21時間後に71,84および98％のかなり良好な収率が達成された。表1の残りの2つのエントリー（エントリー9および10）は、2 -n-ブチルチオフェンとブロモベンゼンneおよび4-ブロモアニソールである。これらの反応の最初のものは複合体8によって触媒され、110℃で1時間後に97％の収率が達成された（表1、項目9）。第2の反応は錯体5によって触媒され、130℃で1時間後に収率79％を与えた（表1、エントリー10）。 ボロン酸誘導体と塩化アリールとの間の研究された鈴木 - 宮浦反応に対する錯体の触媒効果は可変であった（表2）。ここでは、これらの反応の触媒作用における4つの錯体の性能を比較することが目的であったので、検討した各反応について、他の反応条件を一定に保った：2mL：2mLのDMF-水混合物を溶媒、ナトリウムtert-ブトキシドを塩基として使用し、反応を2時間行い、反応温度を80℃に保った。これらの条件下で、複合体5-8は、それぞれ67,55,77および25％の転化率をもたらし、収率は56,51および56であった。2,5-ジメトキシフェニルボロン酸と4-メトキシ-1-クロロベンゼンとの反応については59％および9％であった（表2、項目1〜4）。これらの条件下での4-tert-ブチルフェニルボロン酸と4-クロロトルエンとの反応のために、4つの錯体5-8のすべてが優れた触媒であることが判明し、99,99,98および100％の転化率をもたらし、収率は92,95 、93および99.9％であった（表2、項目5-8）。最後に、これらの条件下でのチアナフテン-2-ボロン酸と1-クロロ-4-ニトロベンゼンとの反応のために、錯体5-8はそれぞれ5,9,55および30％の転化率をもたらし、 35％および14％であった（表2、項目9〜12）。 <img alt="図1" class="xfigimg" src="/files/ftp_upload/54932/54932fig1.jpg" /> 図1 ：ベンズイミダゾリウム塩の合成。 ベンズイミダゾリウム塩を形成するための1-アルキルベンズイミダゾールと種々のハロゲン化アルキルとの間の反応の模式図&lt;強い&gt; 1-4。 <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54932/54932fig1large.jpg" target="_blank">この図の拡大版を見るには、ここをクリックしてください。</a> <img alt="図2" class="xfigimg" src="/files/ftp_upload/54932/54932fig2.jpg" /> 図2 ：パラジウムNHC錯体の合成。 パラジウムNHC錯体5-8を形成するためのベンズイミダゾリウム塩1-4 、塩化パラジウム、炭酸カリウムおよび3-クロロピリジン間の反応の略図。 <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54932/54932fig2large.jpg" target="_blank">この図の拡大版を見るには、ここをクリックしてください。</a> <img alt="表1" src="/files/ftp_upload/54932/54932tbl1.jpg" /> 表1： 触媒されたアリール化反応 - 代表的なresults。 合成されたパラジウムNHC錯体の存在下でのヘテロアリール誘導体の種々のアリール臭化物によるアリール化。反応条件：2 -n-ブチルチオフェンまたは2 -n-ブチルフラン（2mmol）、臭化アリール（4-ブロモアセトフェノン、ブロモベンゼンまたは4-ブロモアニソール）（1mmol）、NHC錯体（ 5~8 ）（0.01mmol）酢酸カリウム（1mmol）、DMA（2mL）、80〜130℃、1〜21時間。 <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54932/54932tbl1large.jpg" target="_blank">この表のより大きなバージョンを表示するには、ここをクリックしてください。</a> <img alt="表2" src="/files/ftp_upload/54932/54932tbl2.jpg" /> 表2： 触媒された鈴木 - 宮浦反応 - 代表的な結果。 合成パラジウムNHC錯体の存在下で、ボロン酸誘導体とアリールクロライドとの鈴木 - 宮浦クロスカップリング反応。反応条件：ボロ（1.5mmol）、塩化アリール（1mmol）、ナトリウムtert-ブトキシド（2mmol）、パラジウムNHC錯体（ 5~8 ）（0.01mmol）、DMF-水（2mL：2mL）、80℃ C、2時間。 <a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54932/54932tbl2large.jpg" target="_blank">この表のより大きなバージョンを表示するには、ここをクリックしてください。</a>

Watch this Scientific Journal Video about Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions at JoVE.com

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

ベンズイミダゾリウム塩からの4つのパラジウムN複素環カルベン錯体の合成およびその後の精製のための詳細で一般化されたプロトコールが提示される。錯体は、アリール化および鈴木 - 宮浦反応における触媒活性について試験された。調査した各反応について、4つの錯体の少なくとも1つが反応を首尾よく触媒した。

パラジウム<em&gt; N</em&gt; - 複素環カルベン錯体：ベンズイミダゾリウム塩からの合成と炭素 - 炭素結合形成反応における触媒活性

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from ...

palladium-n-heterocyclic-carbene-complexes-synthesis-from

Nanyang Technological University

Research

Education

JoVE Journal

JoVE Core

Chemistry

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Chemical Bonding: Basic Concepts

SCIENTISTS IN ACTION

9.6K ビュー.  The University of Sydney. ベンズイミダゾリウム塩からの4つのパラジウムN複素環カルベン錯体の合成およびその後の精製のための詳細で一般化されたプロトコールが提示される。錯体は、アリール化および鈴木 - 宮浦反応における触媒活性について試験された。調査した各反応について、4つの錯体の少なくとも1つが反応を首尾よく触媒した。 

ビデオ: Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Preparation and Use of Samarium Diiodide (SmI2) in Organic Synthesis: The Mechanistic Role of HMPA and Ni(II) Salts in the Samarium Barbier Reaction

Although initially considered an esoteric reagent, SmI2 has become a common tool for synthetic organic chemists. SmI2 is generated through the addition of molecular iodine to samarium metal in THF.1,2-3 It is a mild and selective single electron reductant and its versatility is a result of its ability to initiate a wide range of reductions including C-C bond-forming and cascade or sequential reactions. SmI2 can reduce a variety of functional groups including sulfoxides and sulfones, phosphine oxides, epoxides, alkyl and aryl halides, carbonyls, and conjugated double bonds.2-12 One of the fascinating features of SmI-2-mediated reactions is the ability to manipulate the outcome of reactions through the selective use of cosolvents or additives. In most instances, additives are essential in controlling the rate of reduction and the chemo- or stereoselectivity of reactions.13-14 Additives commonly utilized to fine tune the reactivity of SmI2 can be classified into three major groups: (1) Lewis bases (HMPA, other electron-donor ligands, chelating ethers, etc.), (2) proton sources (alcohols, water etc.), and (3) inorganic additives (Ni(acac)2, FeCl3, etc).3
Understanding the mechanism of SmI2 reactions and the role of the additives enables utilization of the full potential of the reagent in organic synthesis. The Sm-Barbier reaction is chosen to illustrate the synthetic importance and mechanistic role of two common additives: HMPA and Ni(II) in this reaction. The Sm-Barbier reaction is similar to the traditional Grignard reaction with the only difference being that the alkyl halide, carbonyl, and Sm reductant are mixed simultaneously in one pot.1,15 Examples of Sm-mediated Barbier reactions with a range of coupling partners have been reported,1,3,7,10,12 and have been utilized in key steps of the synthesis of large natural products.16,17 Previous studies on the effect of additives on SmI2 reactions have shown that HMPA enhances the reduction potential of SmI2 by coordinating to the samarium metal center, producing a more powerful,13-14,18 sterically encumbered reductant19-21 and in some cases playing an integral role in post electron-transfer steps facilitating subsequent bond-forming events.22 In the Sm-Barbier reaction, HMPA has been shown to additionally activate the alkyl halide by forming a complex in a pre-equilibrium step.23
Ni(II) salts are a catalytic additive used frequently in Sm-mediated transformations.24-27 Though critical for success, the mechanistic role of Ni(II) was not known in these reactions. Recently it has been shown that SmI2 reduces Ni(II) to Ni(0), and the reaction is then carried out through organometallic Ni(0) chemistry.28
These mechanistic studies highlight that although the same Barbier product is obtained, the use of different additives in the SmI2 reaction drastically alters the mechanistic pathway of the reaction. The protocol for running these SmI2-initiated reactions is described.

Preparation and Use of Samarium Diiodide SmI2 in Organic Synthesis: The Mechanistic Role of HMPA and NiII Salts in the Samarium Barbier Reaction

A straightforward procedure for the preparation of samarium diiodide (SmI2) in THF is described. The role of two main additives namely hexamethylphosphoramide (HMPA) and Ni(acac)2 in Sm mediated reactions is demonstrated in the Sm-Barbier reaction.

二ヨウ化サマリウム（SMIの調製および使用<sub&gt; 2</sub&gt;）有機合成における：サマリウムバルビエ反応におけるHMPAとNi（II）塩の力学的役割

Although initially considered an esoteric reagent, SmI2 has become a common tool for synthetic organic chemists. SmI2 is generated through the addition of ...

化学

Anticancer Metal Complexes: Synthesis and Cytotoxicity Evaluation by the MTT Assay

Titanium (IV) and vanadium (V) complexes are highly potent anticancer agents. A challenge in their synthesis refers to their hydrolytic instability; therefore their preparation should be conducted under an inert atmosphere. Evaluation of the anticancer activity of these complexes can be achieved by the MTT assay.
The MTT assay is a colorimetric viability assay based on enzymatic reduction of the MTT molecule to formazan when it is exposed to viable cells. The outcome of the reduction is a color change of the MTT molecule. Absorbance measurements relative to a control determine the percentage of remaining viable cancer cells following their treatment with varying concentrations of a tested compound, which is translated to the compound anticancer activity and its IC50 values. The MTT assay is widely common in cytotoxicity studies due to its accuracy, rapidity, and relative simplicity.
Herein we present a detailed protocol for the synthesis of air sensitive metal based drugs and cell viability measurements, including preparation of the cell plates, incubation of the compounds with the cells, viability measurements using the MTT assay, and determination of IC50 values.

A method for synthesis of air-sensitive titanium and vanadium anticancer agents is described, along with the evaluation of their cytotoxic activity towards human cancer cell line by the MTT Assay.

MTTアッセイにより合成と細胞毒性の評価：抗がん金属錯体

Titanium (IV) and vanadium (V) complexes are highly potent anticancer agents. A challenge in their synthesis refers to their hydrolytic instability; ...

Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols

Unsymmetrical 1,2-diols are hardly accessible by reductive pinacol coupling processes. A successful execution of such a transformation is bound to a clear recognition and strict differentiation of two similar carbonyl compounds (aldehydes &#8594; secondary 1,2-diols or ketones &#8594; tertiary 1,2-diols). This fine-tuning is still a challenge and an unsolved problem for an organic chemist. There exist several reports on successful execution of this transformation but they cannot be generalized. Herein we describe a catalytic direct pinacol coupling process which proceeds via a retropinacol/cross-pinacol coupling sequence. Thus, unsymmetrical substituted 1,2-diols can be accessed with almost quantitative yields by means of an&#160;operationally simple performance under very mild conditions. Artificial techniques, such as syringe-pump techniques or delayed additions of reactants are not necessary. The procedure we describe provides a very rapid access to cross-pinacol products (1,2-diols, vicinal diols). A further extension of this new process, e.g. an enantioselective performance could provide a very useful tool for the synthesis of unsymmetrical chiral 1,2-diols.

A novel account for the synthesis of unsymmetrical 1,2-diols based on a retropinacol/cross-pinacol coupling mechanism is described. Due to the catalytic execution of this reaction a considerable improvement compared to conventional cross-pinacol couplings is achieved.

Retropinacol /クロスピナコールカップリング反応 -  1,2  - 非対称ジオールに対して触媒のアクセス

Unsymmetrical 1,2-diols are hardly accessible by reductive pinacol coupling processes. A successful execution of such a transformation is bound to a clear ...

Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium Under Mild Reaction Conditions

Dichloro-bis(aminophosphine) complexes of palladium with the general formula of [(P{(NC5H10)3-n(C6H11)n})2Pd(Cl)2] (where n = 0-2), belong to a new family of easy accessible, very cheap, and air stable, but highly active and universally applicable C-C cross-coupling catalysts with an excellent functional group tolerance. Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium [(P(NC5H10)3)2Pd(Cl)2] (1), the least stable complex within this series towards protons; e.g. in the form of water, allows an eased nanoparticle formation and hence, proved to be the most active Heck catalyst within this series at 100 &#176;C and is a very rare example of an effective and versatile catalyst system that efficiently operates under mild reaction conditions. Rapid and complete catalyst degradation under work-up conditions into phosphonates, piperidinium salts and other, palladium-containing decomposition products assure an easy separation of the coupling products from catalyst and ligands. The facile, cheap, and rapid synthesis of 1,1',1"-(phosphinetriyl)tripiperidine and 1 respectively, the simple and convenient use as well as its excellent catalytic performance in the Heck reaction at 100 &#176;C make 1 to one of the most attractive and greenest Heck catalysts available.
We provide here the visualized protocols for the ligand and catalyst syntheses as well as the reaction protocol for Heck reactions performed at 10 mmol scale at 100 &#176;C and show that this catalyst is suitable for its use in organic syntheses.

Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions

Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium [(P(NC5H10)3)2Pd(Cl)2] (1) is an easy accessible, cheap, and air stable, but highly active Heck catalyst with an excellent functional group tolerance that efficiently operates under mild reaction conditions to give the coupling products in very high yields.

温和な反応条件の下でパラジウム - ジクロロ{ビス[（ホスフィントリ）tripiperidine 1,1 &#39;、1&#39;&#39;]}触媒による溝呂木 - ヘッククロスカップリング反応

Dichloro-bis(aminophosphine) complexes of palladium with the general formula of [(P{(NC5H10)3-n(C6H11)n})2Pd(Cl)2] (where n = 0-2), belong to a new family ...

Synthesis and Catalytic Performance of Gold Intercalated in the Walls of Mesoporous Silica

As a promising catalytically active nano reactor, gold nanoparticles intercalated in mesoporous silica (GMS) were successfully synthesized and properties of the materials were investigated. We used a one pot sol-gel approach to intercalate gold nano particles in the walls of mesoporous silica. To start with the synthesis, P123 was used as template to form micelles. Then TESPTS was used as a surface modification agent to intercalate gold nano particles. Following this process, TEOS was added in as a silica source which underwent a polymerization process in acid environment. After hydrothermal processing and calcination, the final product was acquired. Several techniques were utilized to characterize the porosity, morphology and structure of the gold intercalated mesoporous silica. The results showed a stable structure of mesoporous silica after gold intercalation. Through the oxidation of benzyl alcohol as a benchmark reaction, the GMS materials showed high selectivity and recyclability.

Here, we present a protocol with a sol-gel process to synthesize gold intercalated in the walls of mesoporous materials (GMS), which is confirmed to possess a mesoporous matrix with gold intercalated in the walls imparting great stability and recyclability.

合成とメソポーラスシリカの壁に金インターカレーの触媒性能

As a promising catalytically active nano reactor, gold nanoparticles intercalated in mesoporous silica (GMS) were successfully synthesized and properties ...

Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts

Ynones are a valuable functional group and building block in organic synthesis. Ynones serve as a precursor to many important organic functional groups and scaffolds. Traditional methods for the preparation of ynones are associated with drawbacks including harsh conditions, multiple purification steps, and the presence of unwanted byproducts. An alternative method for the straightforward preparation of ynones from acyl chlorides and potassium alkynyltrifluoroborate salts is described herein. The adoption of organotrifluoroborate salts as an alternative to organometallic reagents for the formation of new carbon-carbon bonds has a number of advantages. Potassium organotrifluoroborate salts are shelf stable, have good functional group tolerance, low toxicity, and a wide variety are straightforward to prepare. The title reaction proceeds rapidly at ambient temperature in the presence of a Lewis acid without the exclusion of air and moisture. Fair to excellent yields may be obtained via reaction of various aryl and alkyl acid chlorides with alkynyltrifluoroborate salts in the presence of boron trichloride.

The goal of this manuscript is to demonstrate a straightforward method for the preparation of ynones from acyl chloride and potassium alkynyltrifluoroborate salt starting materials. The one-pot reaction proceeds rapidly in the presence of boron trichloride without exclusion of air and moisture.

アシル塩化物およびカリウムAlkynyltrifluoroborate塩からYnonesの金属を含まない合成

Ynones are a valuable functional group and building block in organic synthesis. Ynones serve as a precursor to many important organic functional groups ...

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes

Herein we report the synthesis of a tridentate phosphine ligand N(CH2PPh2)3 (N-triphosPh) (1) via a phosphorus based Mannich reaction of the hydroxylmethylene phosphine precursor with ammonia in methanol under a nitrogen atmosphere. The N-triphosPh ligand precipitates from the solution after approximately 1 hr of reflux and can be isolated analytically pure via simple cannula filtration procedure under nitrogen. Reaction of the N-triphosPh ligand with [Ru3(CO)12] under reflux affords a deep red solution that show evolution of CO gas on ligand complexation. Orange crystals of the complex [Ru(CO)2{N(CH2PPh2)3}-&#954;3P] (2) were isolated on cooling to RT. The 31P{1H} NMR spectrum showed a characteristic single peak at lower frequency compared to the free ligand. Reaction of a toluene solution of complex 2 with oxygen resulted in the instantaneous precipitation of the carbonate complex [Ru(CO3)(CO){N(CH2PPh2)3}-&#954;3P] (3) as an air stable orange solid. Subsequent hydrogenation of 3 under 15 bar of hydrogen in a high-pressure reactor gave the dihydride complex [RuH2(CO){N(CH2PPh2)3}-&#954;3P] (4), which was fully characterized by X-ray crystallography and NMR spectroscopy. Complexes 3 and 4 are potentially useful catalyst precursors for a range of hydrogenation reactions, including biomass-derived products such as levulinic acid (LA). Complex 4 was found to cleanly react with LA in the presence of the proton source additive NH4PF6 to give [Ru(CO){N(CH2PPh2)3}-&#954;3P{CH3CO(CH2)2CO2H}-&#954;2O](PF6) (6).

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes

Ruthenium phosphine complexes are widely used for homogeneous catalytic reactions such as hydrogenations. The synthesis of a series of novel tridentate ruthenium complexes bearing the N-triphos ligand N(CH2PPh2)3 is reported. Additionally, the stoichiometric reaction of a dihydride Ru&#8211;N-triphos complex with levulinic acid is described.

ルテニウムのシリーズの合成、キャラクタリゼーションと反応性<em&gt; N</em&gt; -triphos<sup&gt; Phで</sup&gt;錯体

Herein we report the synthesis of a tridentate phosphine ligand N(CH2PPh2)3 (N-triphosPh) (1) via a phosphorus based Mannich reaction of the ...

Laboratory Production of Biofuels and Biochemicals from a Rapeseed Oil through Catalytic Cracking Conversion

The work is based on a reported study which investigates the processability of canola oil (bio-feed) in the presence of bitumen-derived heavy gas oil (HGO) for production of transportation fuels through a fluid catalytic cracking (FCC) route. Cracking experiments are performed with a fully automated reaction unit at a fixed weight hourly space velocity (WHSV) of 8 hr-1, 490-530 &#176;C, and catalyst/oil ratios of 4-12 g/g. When a feed is in contact with catalyst in the fluid-bed reactor, cracking takes place generating gaseous, liquid, and solid products. The vapor produced is condensed and collected in a liquid receiver at -15 &#176;C. The non-condensable effluent is first directed to a vessel and is sent, after homogenization, to an on-line gas chromatograph (GC) for refinery gas analysis. The coke deposited on the catalyst is determined in situ by burning the spent catalyst in air at high temperatures. Levels of CO2 are measured quantitatively via an infrared (IR) cell, and are converted to coke yield. Liquid samples in the receivers are analyzed by GC for simulated distillation to determine the amounts in different boiling ranges, i.e., IBP-221 &#176;C (gasoline), 221-343 &#176;C (light cycle oil), and 343 &#176;C+ (heavy cycle oil). Cracking of a feed containing canola oil generates water, which appears at the bottom of a liquid receiver and on its inner wall. Recovery of water on the wall is achieved through washing with methanol followed by Karl Fischer titration for water content. Basic results reported include conversion (the portion of the feed converted to gas and liquid product with a boiling point below 221 &#176;C, coke, and water, if present) and yields of dry gas (H2-C2's, CO, and CO2), liquefied petroleum gas (C3-C4), gasoline, light cycle oil, heavy cycle oil, coke, and water, if present.

This paper presents an experimental method to produce biofuels and biochemicals from canola oil mixed with a fossil-based feed in the presence of a catalyst at mild temperatures. Gaseous, liquid, and solid products from a reaction unit are quantified and characterized. Conversion and individual product yields are calculated and reported.

接触分解変換により菜種油からバイオ燃料および生化学の研究室の生産

The work is based on a reported study which investigates the processability of canola oil (bio-feed) in the presence of bitumen-derived heavy gas oil ...

Enzymatic Cascade Reactions for the Synthesis of Chiral Amino Alcohols from L-lysine

Amino alcohols are versatile compounds with a wide range of applications. For instance, they have been used as chiral scaffolds in organic synthesis. Their synthesis by conventional organic chemistry often requires tedious multi-step synthesis processes, with difficult control of the stereochemical outcome. We present a protocol to enzymatically synthetize amino alcohols starting from the readily available L-lysine in 48 h. This protocol combines two chemical reactions that are very difficult to conduct by conventional organic synthesis. In the first step, the regio- and diastereoselective oxidation of an unactivated C-H bond of the lysine side-chain is catalyzed by a dioxygenase; a second regio- and diastereoselective oxidation catalyzed by a regiodivergent dioxygenase can lead to the formation of the 1,2-diols. In the last step, the carboxylic group of the alpha amino acid is cleaved by a pyridoxal-phosphate (PLP) decarboxylase (DC). This decarboxylative step only affects the alpha carbon of the amino acid, retaining the hydroxy-substituted stereogenic center in a beta/gamma position. The resulting amino alcohols are therefore optically enriched. The protocol was successfully applied to the semipreparative-scale synthesis of four amino alcohols. Monitoring of the reactions was conducted by high performance liquid chromatography (HPLC) after derivatization by 1-fluoro-2,4-dinitrobenzene. Straightforward purification by solid-phase extraction (SPE) afforded the amino alcohols with excellent yields (93% to &#62;95%).

Chiral amino alcohols are versatile molecules for use as scaffolds in organic synthesis. Starting from L-lysine, we synthesize amino alcohols by an enzymatic cascade reaction combining diastereoselective C-H oxidation catalyzed by dioxygenase followed by cleavage of the carboxylic acid moiety of the corresponding hydroxyl amino acid by a decarboxylase.

L リジンから光学活性アミノ アルコールの合成酵素連鎖反応

Amino alcohols are versatile compounds with a wide range of applications. For instance, they have been used as chiral scaffolds in organic synthesis. ...

Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area

We demonstrate a method for the synthesis of NixNb1-xO catalysts with sponge-like and fold-like nanostructures. By varying the Nb:Ni ratio, a series of NixNb1-xO nanoparticles with different atomic compositions (x = 0.03, 0.08, 0.15, and 0.20) have been prepared by chemical precipitation. These NixNb1-xO catalysts are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The study revealed the sponge-like and fold-like appearance of Ni0.97Nb0.03O and Ni0.92Nb0.08O on the NiO surface, and the larger surface area of these NixNb1-xO catalysts, compared with the bulk NiO. Maximum surface area of 173 m2/g can be obtained for Ni0.92Nb0.08O catalysts. In addition, the catalytic hydroconversion of lignin-derived compounds using the synthesized Ni0.92Nb0.08O catalysts have been investigated.

Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area

A protocol for the synthesis of sponge-like and fold-like Ni1-xNbxO nanoparticles by chemical precipitation is presented.

Nb2O5の合成化学沈殿法変更高表面積一括ニッケル触媒

We demonstrate a method for the synthesis of NixNb1-xO catalysts with sponge-like and fold-like nanostructures. By varying the Nb:Ni ratio, a series of ...