Green, B.S., Department of Structural Chemistry, Weizmann Institute of Science, Rehovot, Israel
Rabinsohn, Y., Department of Structural Chemistry, Weizmann Institute of Science, Rehovot, Israel
Rejto, M., Department of Structural Chemistry, Weizmann Institute of Science, Rehovot, Israel

Intramolecular photocycloaddition takes place when a solution of mannitol hexacinnamate is irradiated (λ > 290 nm) and, after ester exchange with excess of methanol and chromatographic separation, methyl cinnamate, dimethyl β-truxinate, (±)-dimethyl neo-truxi-nate, and (+)-dimethyl δ-truxinate are isolated; the optical yield of the latter is as high as 46%.