STEREOCHEMISTRY OF BICYCLO[3.2.1]OCTANE .18. ADDITION OF MONOCHLOROCARBENE TO BICYCLO[2.2.2]OCTENE-2, 1-METHYL- AND 2-METHYLNORBORNENE-2

Monochlorocarbene undergoes addition to bicyclo[2.2.2]octene-2 to give anti- and syn-3-chlorotricyclo[3.2.2.02,4]nonane in a ratio of 5:1. On warming the mixture, only the syn isomer rearranges to 2-chlorobicyclo[3.2.2]nonene-3. The addition of monochlorocarbene to 1-methylnorbomene-2 affords 1-methyl-anti-3-chloro-exo-tricyclo[3.2.1.02,4]octane. 1-methyl-exo-4-chlorobicyclo[3.2.1]octene-2 and 1-methyl-exo-2-chlorobicyclo[3.2.1]octene-3 in a ratio of 3:1:1. Similar addition to 2-methylnorbomene-2 gives 2-methyl-anti-3-chloro-exo-tricyclo[3.2.1.02,4]octane and 2-methylenebicyclo[3.2.1]octene-3 in a ratio of 10:1. The exo-anti tricyclic structures are stable to heat and aqueous silver ion. In contrast, the exo-syn adducts are remarkably labile and are assumed to be the precursors of the rearranged products. The factors which govern the stereochemistry of the addition and rearrangement processes are discussed. © 1969.