Preparation of a chiral azadiene for the synthesis of 5-aza analogues of angucyclinones

We have developed an efficient synthesis of both enantiomers of a key azadiene for the preparation of 5-aza analogues of angucyclinones through a hetero Diels-Alder reaction. These dienes were efficiently prepared via a 4-step procedure from known and readily available chiral diketoesters. (C) 2011 Elsevier Ltd. All rights reserved.