Catalytic Enantioselective Allylation of Ketoimines
摘要:
A general catalytic allylation of simple ketoimines was developed using 1 mol % of CuF(.)3PPh(3) as catalyst, 1.5 mol % of La((OPr)-Pr-/)(3) as the cocatalyst, and stable and nontoxic allylboronic acid pinacol ester as the nucleophile. This reaction constituted a good template for developing the first catalytic enantioselective allylation of ketoimines. In this case, using (LiOPr)-Pr-i as the cocatalyst produced higher enantioselectivity and reactivity than La((OPr)-Pr-i)(3). Thus, using the CuF-cyclopentyl-DuPHOS complex ( 10 mol %) and (LiOPr)-Pr-i ( 30 mol %) in the presence of tBuOH (1 equiv) produced high enantioselectivity up to 93% ee from a range of aromatic ketoimines. Mechanistic studies indicated that (LiOPr)-Pr-i accelerates the reaction by increasing the concentration of an active nucleophile, allylcopper.
KOBu<sup>t</sup>/DMSO-Mediated α-C–H Vinylation of <i>N</i>-Benzyl Ketimines with Acetylene Gas: Stereoselective Synthesis of (<i>E</i>,<i>Z</i>)-2-Azadienes
作者:Ivan A. Bidusenko、Elena Yu. Schmidt、Nadezhda I. Protsuk、Igor A. Ushakov、Alexander V. Vashchenko、Andrei V. Afonin、Boris A. Trofimov
DOI:10.1021/acs.orglett.0c00564
日期:2020.4.3
Several imines, readily derived from aryl methyl ketones and benzylamines, react with acetylene gas in KOBut/DMSO system to afford 2-azadienes stereoselectively. This new C–C bond constructing reaction involves, instead of the expected ethynylation of the C═N bond, the addition of azaallyl anions to the triple bond of acetylene.
易于衍生自芳基甲基酮和苄胺的几种亚胺在KOBu t / DMSO系统中与乙炔气体反应,以立体选择性地得到2-氮杂二烯。这种新的C–C键构建反应涉及将乙二烯丙基阴离子加到乙炔的三键上,而不是C═N键的预期乙炔化。
Catalytic Asymmetric Hydrogenation of Imines with a Chiral Titanocene Catalyst: Scope and Limitations
作者:Christopher A. Willoughby、Stephen L. Buchwald
DOI:10.1021/ja00099a012
日期:1994.10
The asymmetric hydrogenation of imines with a chiral titanocene catalyst derived from Brintzinger's ansatitanocene complex 1 proceeds to afford amines with good to excellent enantioselectivity. The catalyst is particularly effective for the reduction of cyclic imines. For these substrates enantiomeric excesses from 95 to 99% were achieved. For acyclic imines lower enantiomeric excesses were observed. The reason for this is likely due to the fact that the acyclic imines are mixtures of anti and syn isomers which interconvert during the reaction. The catalyst was found to be tolerant of many functional groups found in organic synthesis. Thus the reaction represents an effective method for the synthesis of chiral cyclic amines.