Assembly of Dimethyl Acetylenedicarboxylate and Phosphanes with Aldehydes Leading to γ‐Lactones Bearing α‐Phosphorus Ylides as Wittig Reagents

We report herein a convenient route to the synthesis of aryl-substituted γ-lactones bearing an α-phosphorus ylide moiety through the assembly of dimethyl acetylenedicarboxylate (DMAD), electron-deficient aldehydes, and triaryl- or trialkylphosphanes in moderate to good yields. The formation of γ-lactones is highly dependent on the reaction time, the phosphane nucleophile, and the molar ratio of DMAD, aldehyde, and phosphane. We found that reactions with a DMAD/aldehyde/tri-p-tolylphosphane molar ratio of 3:1:6 and more electron-deficient aldehydes, such as 4-nitrobenzaldehyde and 4-chloro-3-nitrobenzaldehyde, gave good yields. The isolated ylides reacted with aldehydes as Wittig reagents to give olefins in moderate yields.