Photochemical Selenosulfonation of Tricyclo[4.1.0.02,7]heptane Derivatives

Se-Phenyl methane-, benzene-, and 4-methylbenzenesulfonoselenoates PhSeSO2R (R = Me, Ph, 4-MeC6H4) react with 1-X-tricyclo[4.1.0.02,7]heptanes (X = Me, Ph, SiMe3) under photochemical initiation to give products of addition at the C1–C7 central bicyclobutane bond with a bicyclo[3.1.1]heptane (norpinane) skeleton, where the R-sulfonyl group is attached to C7 and is oriented syn and the phenylselanyl group on C6 can occupy both syn and anti positions. Radical mechanism of the reaction and its stereochemistry are discussed.