1,4-bis(arylsulfonyl)-1,2,3,4-tetrahydropyridines in synthesis. Intramolecular alkylation reactions and stereoselective synthesis of anti-2,6-disubstituted piperidines

1,4-Bis(arylsulfonyl)-1,2,3,4-tetrahydropyridines 1 having R-1 containing aromatic groups undergo intramolecular electrophilic aromatic substitution reactions to give benzo-fused bicyclo[3,3,1] systems with chemoselectivities which depend on the nature of the acidic reagent used. Cationic hydrogenation of the C-5-C-6 double bond in substrates 1 substituted at C-6 provides an entry to anti-2,6-disubstituted piperidines upon desulfonylation.