Solid-state photodimerization of 2-phenylethenyl enamides

Article abstract of DOI:10.1016/S0040-4020(98)00806-0

Enamides 3a-c and 6 crystallize in α-packing modes with short intermolecular distances of 3.7-4.0 A between alkene carbon atoms of adjacent molecules related by a center of symmetry. Irradiation at 350 nm of these crystalline tertiary phenylethenyl enamides affords head-to-tail dimers 8a-c and 9, respectively, in 87-92% yield, in marked contrast to the E to Z isomerization that is the exclusive reaction upon solution irradiation of enamides 3a and 6.