Photoaddition of Vinyl Ethers to N-Methylphtalimide. Competing 2+2 Processes

Abstract

The photochemical addition of vinyl alkyl ethers to N-methylphthalimide to give 3.4-benzo-6,7-dihydro-1- methylazepine-2,s-diones in a ?r2 + a2 process is found to compete with the ?r2 + 7r2 Paterno-Buchi reaction in this system.The photochemical reactions of phthalimides have been the subject of numerous recent reports.The system undergoes a variety of photoreactions common to other carbonyl compounds including Type I1 and photoreduction reactions.' We recently reported2 the novel addition of a series of dienes to N-methylphthalimide (1) to give 6-substituted 3,4-benzo--