Chiroptical molecular switch

Abstract

Methyl(methoxythioxanthylidene)phenanthrenes I (R = MeO, R1 = H, R22 = bond; R = H, R1 = MeO, R22 = bond) were prepd. and underwent photochem. cis-trans isomerization. Thus, 2,3-dihydro-7-methylhydrazone-4(1H)-phenanthrene was converted to its diazo compd. which cyclocondensed with 9H-thioxanthene-2-methoxy-9-thione to give I (R = MeO, R1 = H, R22 = S; R = H, R1 = MeO, R22 = S) which were desulfurized to give I (R = MeO, R1 = H, R22 = bond; R = H, R1 = MeO, R22 = bond). CD and UV spectra of the products were recorded. [on SciFinder (R)]