Y. Sonoda et al., Intermolecular [2+2] photocycloaddition of formyl- and cyano-substituted diphenylhexatrienes in the solid state, CHEM LETT, (5), 2001, pp. 410-411
Crystalline powder of all-trans-1,6-bis(4-R-phenyl)-1,3,5-hexatriene (R = C
HO and CN) underwent intermolecular [2+2] photocycloaddition at the 1,2-pos
ition of the triene to give mirror symmetric dimers. For the formyl derivat
ive the presence of C-H . . .O hydrogen bonds was suggested by IR and C-13
CP/MAS NMR spectra.