Rearrangement of a mesylate tropane intermediate in nucleophilic substitution reactions. Synthesis of aza-bicyclo[3.2.1]octane and aza-bicyclo[3.2.2]nonane ethers, imides, and amines

Abstract

Nucleophilic substitution of 2β-mesyloxymethyl-N-methyl-3β-p-tolyl-tropane intermediate with alkoxides, metal imides, or amines was found to lead not only to the expected bicyclo[3.2.1]octane (tropane) ether, imide, and amine derivatives but also to unexpected bicyclo[3.2.2]nonane derivatives. When alkoxides were used as nucleophile, only the rearranged bicyclo[3.2.2]nonane structure was obtained, whereas the use of amines or amides as necleophile afforded a mixture of the two structures. The bicyclo[3.2.2]nonane structure wasa assigned by NMR analysis.