Photochemical Syntheses of 2-Heterobicyclo-[3.2.0] heptane and-[4.2.0] octane Ring Systems

Abstract

Irradiation of 3-(3-butenyloxy)- and 3-(4-pentenyloxy)-5, 5-dimethyl-2-cyclohexen-1-ones resulted in an intramolecular cycloaddition to give the corresponding 2-oxabicyclo-[n.2.0] alkanes rather than the 2-oxabicyclo [n.1.1] alkanes. Similarly 3-(N-acetyl-N-3-butenylamino)- and 3-(N-acetyl-N-4-pentenylamino)-5, 5-dimethyl-2-cyclohexen-1-ones afforded the 2-azabicyclo [n.2.0] alkanes. Some of the ring opening reactions of these photoadducts are also described.