Deamination of endo- and exo-bornylamines and related reactions

Abstract

Deamination of the epimeric bornylamines with sodium nitrite–acetic acid mainly gave rearranged products with the isocamphane skeleton but the endo-isomer uniquely formed 7% of monocyclic products. Acetolysis of ethereal diazocamphane and decomposition of N-acetyl-N-nitroso-endo-bornylamine in ethereal acetic acid formed 2% and none of the latter products, respectively. The last two reactions gave larger yields of exo-borneol and tricyclene than the first, and tracer studies revealed that formation of tricyclene from diazocamphane involved a cationic rather than a carbenoid route. The three types of reactions probably proceeded by formation of secondary and rearranged tertiary carbonium ions which although formally equivalent in the various examples differed in their counter fragment.

Monocyclic products were not formed on treatment of endo-borneol or endo-bornyl chloride with Lewis acids in aprotic media, but in contrast with the deaminations some of the products were partially racemised.