Topochemical Double Photocyclodimerization of Ris(butoxycarbonyl)-Substituted Tetrathiafulvalene in the Crystalline State

Crystals of bis(butoxycarbonyl)-substituted tetrathiafulvalene having three reactive double bonds yield upon irradiation two products, a “cage product” (II) as well as another (I) by the participation of a pair of reactive double bonds. The formation of both the products is understood based on the molecular packing in the crystal lattice. The circumstances leading to the formation of more than one photoproduct in the crystalline state and the question regarding the sulfur atom as a steering group in the context of crystal engineering are discussed.