ENANTIODIFFERENTIATING PHOTOISOMERIZATION OF 1,2-DIPHENYLCYCLOPROPANE SENSITIZED BY CHIRAL AROMATIC ESTERS

Enantiodifferentiating cis-trans photoisomerization of 1,2-diphenylcyclopropane (1) in the presence of (-)-tetramenthyl 1,2,4,5-benzenetetracarboxylate as a chiral sensitizer gave (+)-(1S,2S)-1t in enantiomeric excesses (e.e.) of 10.4 and 2.8% in pentane and acetonitrile, respectively, while the photosensitization with the corresponding (-)-tetrabornyl ester afforded (+)-(1S,2S)-1t (3.8% e.e.) in pentane and, notably, the antipode (-)-(1R,2R)-1t (2.4% e.e.) in acetonitrile.