A Highly Tunable Stereoselective Olefination of Semistabilized Triphenylphosphonium Ylides with N-Sulfonyl Imines

作者：Dong De Jun; Li Hai Hua; Tian Shi Kai^*

来源：Journal of the American Chemical Society, 2010, 132(14): 5018-+.

DOI：10.1021/ja910238f

The Wittig reaction involving direct olefination of triphenylphosphonium ylides (Ph(3)P=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, which possess distinct electronic and steric properties relative to aldehydes. A broad range of aromatic, alpha,beta-unsaturated, and aliphatic imines bearing appropriate N-sulfonyl groups smoothly undergo olefination reaction with various benzylidenetriphenylphosphoranes or allylidenetriphenylphosphoranes under mild reaction conditions to afford an array of both Z- and E-isomers of conjugated alkenes in good to excellent yields and with greater than 99:1 stereoselectivity. Moreover, this tunable protocol has been successfully applied to the highly stereoselective synthesis of two anticancer agents, DMU-212 and its Z-isomer.

• 出版日期2010-4-14
• 单位中国科学技术大学