Fig. 7: Trapping of alkylidene carbenes 9 and 12.

Photolysis of precursor 22 in the presence of cyclohexene (35) resulted in the formation of adduct 36, the expected product of reaction between 7-norbornylidene carbene (9) and 35. Photolysis of precursor 29 in the presence of 35 resulted in the formation of 39, indicating the reaction of 8-pentacyclo[5.4.0.02,6.03,10.05,9]undecylidene carbene (12) and 35. The identities of adducts 36 and 39 were determined by derivatization to spirocyclopropanes 37 and 40, respectively, and characterization by X-ray crystallography.