Stereoselective construction of tetrasubstituted exocyclic alkenes from the [4+ 2]-cycloaddition of vinylallenes

C Spino, C Thibault, S Gingras

Index: Spino, Claude; Thibault, Carl; Gingras, Stephane Journal of Organic Chemistry, 1998 , vol. 63, # 15 p. 5283 - 5287

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Citation Number: 41

Abstract

In the course of our synthetic studies on quassinoids1 we required the stereoselective preparation of a tetrasubstituted exocyclic double bond of the type shown as structure 1 (eq 1, R1, R2, X* H). 2 Starting from the corresponding 2-X-2-cyclohexen-1-one 2, a wide range of methods were examined to no avail, including Wittig olefination, aldol condensation/ elimination, McMurray coupling, addition of 2-propenyllithium followed by Claisen ...