Synthesis of trans-fused oxabicyclo[5.2.0]nonan-2-ones via [2+2] photocycloaddition of oxepinones to conjugated alkenes

摘要

On irradiation (350 nm) in the presence of 2,3-dimethylbuta-1,3-diene, benzoxepinone 2 and dioxepinone 3 were converted regio- and diastereoselectively to trans-fused oxabicyclo[5.2.0]nonanones 5 and 9, respectively.