Copper(I)-Catalyzed Tandem Carboarylation/Cyclization of Alkynyl Phosphonates with Diaryliodonium Salts

Abstract

A copper-catalyzed tandem carboarylation/cyclization of alkynyl phosphonates with diaryliodonium salts is reported. The reaction gives straightforward access to valuable cyclic enol phosphonates in good yields under mild conditions. This transformation entails an initial chemoselective arylation of the alkyne followed by an intramolecular trapping of an intermediate vinyl cation by the phosphoryl group. Observation of β-aryl rearrangements across the double bond in intermediates generated from 1,2-diaryl alkynes support the intermediacy of a vinyl cation.