Oxadiazinones as chiral auxiliaries: diastereoselective aldol addition reactions of N3-glycolyl-3,4,5,6-tetrahydro-2H-1,3,4-oxadiazin-2-ones
摘要:
Asymmetric aldol reactions have been conducted with a series of N-3-glycolyl-3,4,5,6-tetrahydro-2H-1,3,4-oxadiazin-2-ones derived from (1R,2S)-ephedrine. These reactions afford the non-Evans syn-adducts in 43-97% yield and diastereoselectivities ranging from 62:38 to 99:1. Oxadiazinone substrates substituted with either the phenoxyacetyl or p-methoxyphenoxyacetyl groups gave the best results whereas the methoxyacetyl substituted oxadiazinone afforded diastereoselectivities that were modest. (C) 2003 Elsevier Ltd. All rights reserved.