DEAMINATION REACTIONS .55. DECOMPOSITION OF 2-CYANONORBORNANE-2-DIAZONIUM IONS

The epimeric 2-aminonorbornane-2-carbonitriles (8a and 9a) were prepar ed from norbornane-2-one (7). The nitrous acid deamination reactions o f 8a and 9a afforded the nitro compounds 15c and 16c in low exo/endo r atios, presumably by way of 2-cyano-2-norbornyl radicals (12). The maj or ionic process was found to be a Wagner-Meerwein rearrangement, lead ing to 1-cyano-2-norbornyl cations (10) and products 14 derived theref rom. Minor amounts (less-than-or-equal-to 10%) of 2-hydroxynorbornane- 2-carbonitriles (15a, 16a) provide suggestive, albeit inconclusive evi dence for the trapping of 2-cyano-2-norbornyl cations (11). The decomp osition of the endo diazonium ions 9c is also associated with norborny l --> norpinyl rearrangement, giving rise to 17 (less-than-or-equal-to 9%). Stereochemical studies with optically active precursors point to intervention of the 7-bridged norbornyl cation 13 and of the edge-pro tonated cyclopropane 25. The formation of both species is clearly prom oted by the cyano group.