Conjugate addition nitro-Mannich reaction of carbon and heteroatom nucleophiles to nitroalkenes
作者:James C. Anderson、Andreas S. Kalogirou、Graham J. Tizzard
DOI:10.1016/j.tet.2014.10.042
日期:2014.12
The conjugate addition nitro-Mannich reactions of ethyl-beta-nitroacrylate (1) and beta-nitrostyrene (2) with electron rich aromatic nucleophiles, stabilized carbanions, alcohols, amines, thiols, and diphenyl phosphine oxide were investigated. The one pot conjugate addition nitro-Mannich reaction was unsuccessful except for the addition of alkoxides to 2 in alcohol as solvent. Isolation of the conjugate addition products followed by deprotonation with (BuLi)-Bu-n and treatment with a simple imine in the presence of TFA led to beta-nitroamine derived products. Products derived from 1 spontaneously cyclised in only a few examples and on the whole led to inherently unstable products. Products derived from 2 were isolated as their trifluoroacetamides, gave good yields of single diastereoisomers for aromatic and alkoxide nucleophiles and the structures were verified by single crystal X-ray crystallography. Products derived from amine nucleophiles were isolated in low yields while sulfur nucleophiles gave poor diastereoselectivities. (C) 2014 Elsevier Ltd. All rights reserved.