Helicenes. Chemically Induced Asymmetric Photosyntheses of a Helicene Skeleton: 2‐ and 3‐Menthyloxycarbonyl [6] Helicene

Abstract Two asymmetric photosyntheses of a [6] helicene skeleton, induced by (‐) menthyl esters, have been studied (Ia–IIa and Ib–IIb). The optical yield of the two reactions is of the same magnitude (5‐6%), but the substituted helicenes produced in excess have opposite configurations.