Regio- and diastereoselective tandem addition–carbocyclization promoted by sulfanyl radicals on chiral perhydro-1,3-benzoxazines
摘要:
Radical addition-carbocyclization of 2-allyl-3-acyloyl-substituted perhydro-1,3-benzoxazines readily provides 3,4-disubstituted pyrrolidinone derivatives with total regioselectivity and good diastereoselectivity. The key step of the reaction is a tandem addition-5-exo-cyclization promoted by a sulfanyl radical. (C) 2003 Elsevier Ltd. All rights reserved.
Synthesis of Enantiopure 3-Azabicyclo[3.2.0]heptanes by Diastereoselective Intramolecular [2+2] Photocycloaddition Reactions on Chiral Perhydro-1,3-benzoxazines
作者:Rafael Pedrosa、Celia Andrés、Javier Nieto、Soledad del Pozo
DOI:10.1021/jo034251c
日期:2003.6.1
[2+2] photocycloadditions involving chiral 3-acryloyl-2-vinylperhydro-1,3-benzoxazines derivedfrom (-)-8-aminomenthol are highly diastereoselectivereactions. The facial selectivity depends on the type of substitution at the vinyl double bond, and always leads to cis-fused bicyclic derivatives. The de is good for compounds with one substituent at the outer carbon of the double bond at C-2, but only