Synthesis of medium-sized cyclic amines by selective ring cleavage of sulfonylated bicyclic amines.

An efficient method of synthesis of functionalized medium-sized cyclic amines (eight- to ten-membered rings) by selective ring opening of sulfonylated bicyclic pyrrolizidine, indolizidine, and quinolizidine compounds is described. The key step is the selective cleavage of the central C-N bond of the bicyclic amine by means of a Julia-like desulfonylation process. Reaction: see text.