Allenyl(vinyl)methane photochemistry. Photochemistry of 4,4,7-trimethyl-5-phenyl-2,5,6-octatrienate derivatives

The direct photolysis of the diester in the title compounds gave a cross conjugated triene, [2+2] cycloadduct, pyran, and cyclopropene. The direct photolysis of the monoester afforded a cross conjugated triene, [2+2] cycloadduct, cyclopropene, and its Z-form. The sensitized photolysis of these esters afforded the trienes and [2+2] cycloadducts, which were derived from the triplet excited state of the different chromophores. (C) 1997 Elsevier Science Ltd.