Diastereoselectivity in (2 pi+2 pi) photocycloaddition of cholesteryl cinnamate to methyl 9-phenanthrenecarboxylate: Control of the stereoselectivity in liquid crystalline phase

摘要

Photocycloaddition of cholesteryl cinnamate with methyl 9-phenanthrenecarboxylate in benzene at ambient temperature gave a (2pi + 2pi) photocycloadduct in 8% diastereomeric excess (de). When the reaction was carried out in neat conditions at 150-170degreesC, the major product was reversed to another diastereomer, in which de was given in 14%.