The ‘inverse electron-demand’ Diels–Alder reaction in polymer synthesis. Part 1. A convenient synthetic route to diethynyl aromatic compounds

Abstract

The simple procedure whereby acetophenone derivatives are converted, by reaction with phosphoryl chloride and N,N-dimethylformamide, into β-chlorocinnamaldehydes, and thence, by base-induced elimination, into ethynylarenes, has been extended to diketones of the type McCOC₆H₄COMe (m- and p-) and (p-MeCOC₆H₄)₂X (X = O, S, SO₂, CH₂, CO, or a single bond): the corresponding diethynyl compounds are obtained by this route in acceptable yield. 1,3,5-Triacetylbenzene is similarly converted into 1,3,5-triethynylbenzene.