Intermolecular [2+2] Photocycloaddition of Formyl- and Cyano-Substituted Diphenylhexatrienes in the Solid State

Abstract
Crystalline powder of all-trans-1,6-bis(4-R-phenyl)-1,3,5-hexatriene (R = CHO and CN) underwent intermolecular [2+2] photocycloaddition at the 1,2-position of the triene to give mirror symmetric dimers. For the formyl derivative the presence of C–H···O hydrogen bonds was suggested by IR and 13C CP/MAS NMR spectra.