Chiral Lewis Base-Catalyzed, Enantioselective Reduction of Unprotected β-Enamino Esters with Trichlorosilane
作者:Jianheng Ye、Chao Wang、Lin Chen、Xinjun Wu、Li Zhou、Jian Sun
DOI:10.1002/adsc.201501061
日期:2016.3.31
reduction of N‐unsubstituted β‐enamino esters represents a major challenge for asymmetric catalysis. In this paper, the first organocatalytic system that could be used for the asymmetric hydrosilylation of N‐unsubstituted β‐enamino esters has been developed. Using N‐tert‐butylsulfinyl‐L‐proline‐derived amides and L‐pipecolinic acid‐derived formamides as catalyst, a broad range of β‐aryl‐ and β‐alkyl‐substituted
<i>N</i>-Heterocyclic Carbene-Catalyzed Enantioselective Mannich Reactions with α-Aryloxyacetaldehydes
作者:Yasufumi Kawanaka、Eric M. Phillips、Karl A. Scheidt
DOI:10.1021/ja9094044
日期:2009.12.23
N-Heterocyclic carbenes (NHCs) catalyze a new Mannich-type reaction to form beta-amino acid derivatives in high yield and enantioselectivity. The reaction is initiated by the addition of an NHC to an alpha-aryloxyaldehyde followed by elimination of a phenoxide anion which generates an enol/enolate. A Mannich addition to a tosylimine proceeds with excellent control over enantioselectivity. In a new