The Wittig reaction involving direct olefination of triphenylphosphonium ylides (Ph3P CHR) with aldehydes is arguably the most often used method for alkene synthesis, but in general it yields mixtures of Z-and E-alkenes for semistabilized triphenylphosphonium ylides (R= aryl or vinyl). We have developed a simple and efficient protocol to improve the stereoselectivity significantly by replacing the aldehydes used in the Wittig reaction with N-sulfonyl imines, ...
