Phosphane Alkylenes, 52. - Reactions of triphenylphosphoranes with Carbon Dioxide
2-(Triphenylphosphoranylidene) carboxylic acid esters 6 have been synthesized from 1-(trimethylsilylalkylidene)phophoranes 4 and carbon dioxide.The reactions of the ylides 6 with aldehydes 9 lead to α,β-unsaturated silyl esters 10 in good yields and with high (E) stereoselectivity.Thermolysis of 6d affords (oxovinylidene)triphenylphosphorane (7). Key Words: Phosphonium ylides / Wittig reaction