Abstract
Dimethyl triarylmethylphosphonates, 1, 1, 1-triary1-2-alkynes, and triarylmethylcycloalkanes underwent photochemical α, α-elimination of two aryl groups to give biaryl and the corresponding arylcarbene intermediates, respectively. Moreover, 1, 1, 1-tripheny1-2-alkene or methyl triphenylacetate also underwent another type of α, α-elimination of a phenyl group and an alkenyl group or a methoxycarbonyl group to give phenylakene or methyl benzoate, and diphenylcarbene intermediates, respctively. Triarylacetonitrile and (triphenylmethyl) diethylamine mainly underwent C-CN or C-N bond cleavage to give triarylmethane or triarylmethyl methyl ether in methanol solution. These photochemical α, α-eliminations can be understood in terms of a special example of di-π-methane or oxa-di-π-methane rearrangement through a singlet excited state.
