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 ...
