Effect of 3-and 4-Methyl Substituents on the Photocyclization of N-(3-Alkenyl) phthalimides : Synthesis of Pyrroloisoindoles and Pyridoisoindoles

Abstract

Photolysis of N-(3-alkenyl) phthalimides 2 in methanol gave tetrahydro-5H-pyrrolo [2, 1-a] isoindol-5-ones 3 and/or tetrahydropyrido [2, 1-a] isoindol-6 (2H)-ones 4 depending on the degree of substitution at the olefin carbons of 2. Electron transfer followed by the anti-Markownikoff addition of methanol is proposed as a possible pathway.