Tandem nucleophilic addition/oxa-Michael reaction of ortho-formyl chalcones with dimethyl (diazomethyl)phosphonate for the synthesis of phosphine-containing 1,3-disubstituted phthalans

Abstract

A novel base-promoted tandem reaction between ortho-formyl chalcones and dimethyl (diazomethyl)phosphonate has been discovered for the construction of a series of phosphine-containing 1,3-disubstituted phthalans with up to 99% yields. This reaction was amenable to scale up to 1 mmol with 90% yield. The alkyne, which was well-known as the product of Seyferth-Gilbert reagent with aldehyde, was not detected in this reaction.