Photolysis of Vinyl Halides. Preferential Formation of Vinyl Cations by Copper(II) Salts

Article abstract of DOI:10.1021/ja00270a023

Photolysis of vinyl halides in the presence of copper(II) salts in a significant suppression of product formation derived from vinyl radicals.Photolysis of 1,1-diaryl-2-bromopropenes in the presence of copper(II) salts yielded no 1,1-diaryl-2-propenes.Photolysis of other vinyl halides, i.e., 1,1-diaryl-2-iodopropenes, 1,1-diaryl-2-bromoethylenes, and 1-bromo-2-(p-methoxyphenyl)ethylene, also led to a large decrease in the yields of the reduced olefins derived from the vinyl radicals.Copper(II) triflate was found to be more effective for the oxidation of vinyl radicals than copper(II) acetate.These reactions are explained by the intervention of vinylcopper intermediates and the formation of vinyl cations.