Switching of product's chirality in diastereodifferentiating [2+2] photocycloaddition of (E)- versus (Z)-stilbene to chiral fumarate upon direct and charge-transfer-band excitation.
[reaction: see text] Diastereodifferentiating [2+2] photocycloadditions of (E)- and (Z)-stilbenes to bis((R)-1-methylpropyl) fumarate were performed through the direct excitation of stilbenes and the selective excitation of the charge-transfer (CT) complex at various temperatures. The geometrical isomers of stilbene afforded the opposite diastereomers of mu-truxinate in both excitation modes, with a dramatic decrease in the product's diastereoselectivity upon prolonged irradiations.
Saito
Hideaki
H
Department of Applied Chemistry, Osaka University, 2-1 Yamada-oka, Suita 565-0871, Japan.
Mori
Tadashi
T
Wada
Takehiko
T
Inoue
Yoshihisa
Y