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

Abstract

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.

New frontiers in the transition-metal-free synthesis of heterocycles from alkynoates: an overview and current status

“…The coupling of more nucleophilic tricyclohexylphosphine with 4-cyano aldimine furnished the desired product in a poor yield (22%). Consistent with the pre- vious report , 131 electron-withdrawing aldimines were only compatible in the multicomponent reaction.…”

Phosphine Organocatalysis

“…An improved procedure was reported a year later, with the use of tris( p -tolyl)phosphine allowing a lower reaction temperature. 815 In addition to enyne systems, a diyne substrate had also been employed, triggering the same transformation. 816 Furthermore, an example of the use of o -nitrocinnamaldehyde has also been reported.…”

Phosphine‐Catalyzed Reactions with Unsaturated Carbonyl Compounds

“…In 2012, our group reported the synthesis of γ‐lactones exhibiting a α‐phosphorus ylide moiety. In this multicomponent reaction (MCR), dimethyl acetylenedicarboxylate (DMAD) 52 , phosphanes, and electron‐deficient aldehydes 51 were assembled in one step to yield γ‐lactone products bearing α‐phosphorus ylide 53 a in good yields (up to 68%), and 53 b and 53 c were formed as side products (Scheme ) . Furthermore, the γ‐lactone bearing the trimethyl phosphorus ylide moiety reacted with aldehydes to produce olefinic 54 compounds in moderate yields (up to 81%).…”