Chiral solvent-induced asymmetric synthesis; photosynthesis of optically enriched hexahelicene

Abstract

Irradiation of 2-styrylbenzo[c]phenanthrene (1) in chiral solvents affords the optically active hexahelicene with optical yields between 0·2 and 2%; the sign of the optical rotation of the product is not directly related to the absolute configuration of the solvents used, but seems to depend on the position of the largest apolar group at the chiral centre.