Highly enantioselective organocatalysis of the Michael addition of benzyloxyacetaldehyde to nitroolefins
作者:Sripragna Burugupalli、Yupu Qiao、Allan D. Headley
DOI:10.1016/j.tetasy.2017.09.018
日期:2017.11
A novel category of di(N,N-dimethylbenzylamine)prolinol silyl ether catalyst, which when used in conjunction with an acidic co-catalyst, generates an ammonium salt supported organocatalyst. This catalytic system is shown to be very effective for the Michael reaction of benzyloxyacetaldehyde and various nitroolefins in isopropanol. Excellent enantioselectivities (up to 99%) and diastereoselectivities (syn/anti of 75:25) and short reaction times were obtained. The presence of the bulky OTMS group combined with the presence of two large N,N-dimethylbenzyl ammonium ion groups accounts for the effectiveness of this catalytic system. (C) 2017 Elsevier Ltd. All rights reserved.