Formation of a benzobicyclo[4.1.0]heptane lactone by photochemical rearrangement of a steroid ketol. Crystal structure determination of 5-methoxy-des-A-14a-D-homo-14,17-cyclo-oestra-5,7,9-trien-15-one
Abstract
Photochemical rearrangement of 14β-hydroxy-5-methoxy-des-A-oestra-5,7,9,16-tetraen-15-one (1) gives the cyclopropane-lactone (4), the structure of which was established by X-ray crystallographic analysis. The lactone was isolated by reversed-phase high-performance liquid chromatography. A possible concerted mechanism for its formation is discussed.