Expeditious entry to novel 2-methylene-2,3-dihydrofuro[3,2-c] chromen-2-ones from 6-chloro-4-hydroxychromen-2-one and propargylic alcohols

Abstract

A catalytic system consisting of the ruthenium(II) complex [Ru(σ 3-2- C 3H 4Me)(CO)(dppf)][SbF 6] (dppf = 1,1'-bis(diphenylphosphino)ferrocene) and trifluoroacetic acid has been used to promote the coupling of secondary propargylic alcohols with 6-chloro-4-hydroxychromen-2-one. The reactions afforded unusual 2-methylene-2,3- dihydrofuro[3,2-c]chromen-2-ones in good yields.