Template-Assisted Stereoselective Photocyclodimerization of 2-Anthracenecarboxylic Acid by Bispyridinio-Appended γ-Cyclodextrin

Four kinds of bispyridinio-appended γ-cyclodextrin (γ-CD) were prepared to make a molecular flask for controlling the stereoselectivity of photocyclodimerization of 2-anthracenecarboxylate. When the photocyclodimerization of 2-anthracenecarboxylate was carried out in the presence of A,E-bispyridinio-appended γ-CD, the relative yield of one of the configurational isomers, the head-to-head/anti-isomer, was increased 1.8-fold compared to the corresponding yield in the presence of unmodified γ-CD or in the absence of any γ-CD. The optical yields of the photocyclodimerization reaction products also increased more than 10-fold by the addition of bispyridinio-appended γ-CD compared with unmodified γ-CD.