Photochemistry of arylbutadienes. Part 3. Mechanisms of photoaddition of methanol to 1-arylbutadienes

Abstract

The mechanism of formation of methyl ethers from irradiation of 1-arylbutadienes in methanol has been studied by deuterium labelling, fluorescence quenching, sensitisation, and kinetic studies. Cyclopropylmethyl ethers arise by a bicyclobutane mechanism; allyl and homoallyl ethers are formed by reaction of methanol with the ¹B_u-like excited singlet diene to produce carbocation intermediates.