An unusual effect of exo-endo configuration on the quantum yield Φ of photochemical rearrangement of 4-R-substituted 8-phenyl-3,5,10-trioxa-9-azabicyclo-[5,3,0]-8-decenes

Abstract

The dependence has been found of the quantum yield Φ of photochemical rearrangement of the title compounds (where R means ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, 2-furyl, 2-thienyl) on the exo(I) or endo (II) arrangement of the R substituent. The endo derivatives exhibit higher Φ values (0.020-0.041) than the exo derivatives (0.007-0.019). The photochemical rearrangement gives the derivatives of 2-R-6-phenyl-7-formyl-2,4,5,8-tetrahydro-1,3-dioxa-5-azocine as the single products in good yields. The 2-furyl derivative gives polymeric products. The title compounds have been prepared by 1,3-dipolar cycloaddition of benzenenitriloxide to the respective substituted 1,3-dioxep-5-enes.