1,4-Bis(arylsulfonyl)-1,2,3,4-tetrahydropyridines in synthesis. Regio- and stereoselective SN1 reactions

1,4-Bis(4-tolylsulfonyl)-1,2,3,4-tetrahydropyridines undergo stereoselective SN1 reactions with soft carbon nucleophiles in the presence of Lewis acids. Subsequent dihydroxylation of the double bond followed by esterification enables the stereoselective preparation of substituted piperidines.