CROWN ETHER CATALYZED STEREOSPECIFIC SYNTHESIS OF Z- AND E-STILBENES BY WITTIG REACTION IN A SOLID-LIQUID TWO-PHASES SYSTEM

摘要

Potassium hydroxide and a catalytic amount of 18-crown-6 are used, in alternative to the classical Wittig conditions, to prepare very rapidly and stereoselectively Z- and E-stilbenes. In particular, the use of benzyltriphenylphosphonium iodides always leads to a complete Z-stereospecificity, while benzyldiphenylchlorophosphonium salts give a complete E-stereospecificity. (C) 1996 Elsevier Science Ltd [References: 17]