PHOTOLYSIS OF 1,1,1-TRIARYLALK-2-ENES AND 1,1,1-TRIARYLHEPT-2-YNES - A NOVEL GENERATION OF ARYL(ALK-1-ENYL)CARBENES AND ARYL(ALK-1-YNYL)CARBENES

Upon UV irradiation in methanol, 1,1,1-triarylhept-2-ynes underwent an α,α-elimination of two aryl groups to give a biaryl and the corresponding carbene which reacted with methanol to give a 1-aryl-1- methoxyhept-2-yne. 1,1,1-Triphenylalk-2-enes underwent α,α- elimination of two phenyl groups and also elimination of an alkene and a phenyl group to give biphenyl and a 1-phenylalkene respectively. In both cases, the corresponding carbenes were formed and were isolated as methanol insertion products (a 1-methoxy-1-phenylalk-2-ene and diphenylmethyl methyl ether, respectively). A rearrangement product, a 1,1,2-triphenylcyclopropane, was also formed.