A concise approach to chiral chromenes based on levoglucosenone
作者:Аlexander V. Samet、Dmitriy N. Lutov、Sergei I. Firgang、Konstantine A. Lyssenko、Victor V. Semenov
DOI:10.1016/j.tetlet.2011.04.004
日期:2011.6
Levoglucosenone, a chiral alpha,beta-unsaturated ketone derived from cellulose, undergoes a stereoselective domino oxa-Michael-aldol reaction with 2-hydroxybenzaldehydes affording optically active pyrano[3,4-b]chromenes. The latter are further converted into 2H-chromenes via a Beckmann fragmentation reaction. (C) 2011 Elsevier Ltd. All rights reserved.
Synthesis of chiral chromenes from levoglucosenone
作者:A. V. Samet、D. N. Lutov、S. I. Firgang、Yu. V. Nelyubina、V. V. Semenov
DOI:10.1007/s11172-013-0318-4
日期:2013.10
Levoglucosenone, an optically active α,β-unsaturated ketone available from cellulose, undergoes a stereoselective oxa-Michael-aldol domino reaction with 2-hydroxybenzaldehydes with the formation of optically active oxepino[4,5-b]chromen-1-ones. These compounds attacked by nucleophiles undergo recyclization to 4-substituted oxepino[3,4-b]chromen-11a-ols, while their oximes treated with SOCl2 are converted to 3-cyano-2H-chromenes