Photochemical and thermal addition of methanol to 2-phenyl-3,1-benzoxazepine-5-carboxylate: reverse stereoselectivities in the two reactions

Abstract

Irradiation of methyl 2-phenyl-3,1-benzoxazepine-5-carboxylate (1) in methanol affords the (Z)-isomer of methyl 3-methoxy-2-(2-benzamidophenyl) acrylate (Z)-(4) as the major addition product, while thermal reaction of methanol with (1) in the presence of triethylamine gives the (E)-isomer (E)-(4), exclusively; reasons for the observed selectivities are discussed.