2,6-Dibromo- and 2,2-dichlorocyclohexanone react with base in the presence
of various dienes to give 4+3 cycloadducts in fair to good yields. Prelimin
ary studies of the cycloadducts suggest that they are unstable and are reca
lcitrant to nucleophilic addition and cross-metathesis. However, the LAH re
duction products undergo a quasi-Favorskii rearrangement upon treatment wit
h potassium hydride and one cycloadduct derivative was dehalogenated using
radical chemistry. (C) 1999 Elsevier Science Ltd. All rights reserved.