Preparation of unsaturated compounds

摘要

Unsaturated compounds of the formula: <IMAGE> in which: Q denotes alkyloxycarbonyl, cyano or formyl, R1 denotes a saturated or unsaturated aliphatic radical, R2 denotes a hydrogen atom or an alkyl radical, R3 denotes a hydrogen atom or an aliphatic radical and R4 denotes a hydrogen atom or a saturated or unsaturated aliphatic radical which may be substituted, are useful as intermediates in the synthesis of vitamin E.