Template-Directed Photochemical Homodimerization and Heterodimerization Reactions of Cinnamic Acids

We developed a general method for
the selective photochemical homo-
and heterodimerization of cinnamic acid derivatives with the use of
commercially available 1,8-dihydroxynaphthalene as a covalent template.
A variety of symmetrical and unsymmetrical β-truxinic acids
were obtained in high yields and as single diastereomers. The use
of a template not only provides the alignment of the two olefins with
suitable proximity (<4.2 Å) but also allows the heterodimerization
of two different cinnamic acids, leading to unsymmetrical β-truxinic
acid products.