<scp>l</scp>-Piperazine-2-carboxylic Acid Derived <i>N</i>-Formamide as a Highly Enantioselective Lewis Basic Catalyst for Hydrosilylation of <i>N</i>-Aryl Imines with an Unprecedented Substrate Profile
作者:Zhouyu Wang、Mounuo Cheng、Pengcheng Wu、Siyu Wei、Jian Sun
DOI:10.1021/ol060984i
日期:2006.7.1
l-Piperazine-2-carboxylic acid derived N-formamides have been developed as highlyenantioselectiveLewis basic catalysts for the hydrosilylation of N-aryl imines with trichlorosilane. The arene sulfonyl group on N4 was found to be critical for the high enantioselectivity of the catalyst. High isolated yields (up to 99%) and enantioselectivities (up to 97%) were obtained for a broad range of substrates, including
Asymmetricreduction of imines were studied using dialkoxyborane 1. Dihydro-β-carboline 5a showed moderate (42%ee) and N-phenylketimine 10 higher enantioselectivity (73%ee). Asymmetricreduction of ketones with oxazaborolidine 33 showed high ennatioselectivities.
Development of highly enantioselective new Lewis basic N-formamide organocatalysts for hydrosilylation of imines with an unprecedented substrate profile
作者:Pengcheng Wu、Zhouyu Wang、Mounuo Cheng、Li Zhou、Jian Sun
DOI:10.1016/j.tet.2008.09.034
日期:2008.12
ketimines and non-methyl ketimines were catalyzed to afford the desired amines in good to high yield and enantioselectivity. In particular, catalyst 6e enabled the reduction of the difficult bulky ketimines to be highly efficient and enantioselective, affording up to 99% yield and 97% ee. This catalyst proved to prefer the relatively bulkier non-methyl acyclic ketimines to the methyl ketimines as substrate
l-Pipecolinic acid derived Lewis base organocatalyst for asymmetric reduction of N-aryl imines by trichlorosilane: effects of the side amide group on catalytic performances
作者:Zhouyu Wang、Chao Wang、Li Zhou、Jian Sun
DOI:10.1039/c2ob26772a
日期:——
A series of N-formamides derived from pipecolinic acid have been synthesized and tested as Lewisbase catalysts for the enantioselective reduction of N-aryl imines by trichlorosilane. Through the investigation of the structure–efficacy relationship between the side amide group and catalytic performance, several highly effective catalysts were discovered. In particular, arylamido-type catalyst 5i and
Iron-Catalyzed Cross-Coupling of Imidoyl Chlorides with Grignard Reagents
作者:Lars K. Ottesen、Fredrik Ek、Roger Olsson
DOI:10.1021/ol0600234
日期:2006.4.1
[reaction: see text] A general, high yielding rapid iron-catalyzedcross-coupling reaction between Grignard reagents and imidoyl chlorides is described. These reactions are typically completed within 5 min, resulting in high yields of 71-96% using 5% iron catalyst in a THF-NMP solvent mixture. Functionalized imidoyl chlorides (e.g., R = CO(2)Me) gave excellent yields (89%).