Asymmetric synthesis of δ-chloro-β-amino-N-sulfinyl imidates as versatile chiral building blocks for the synthesis of 2,3-disubstituted piperidines

Mannich-type reactions of chiral delta-chloro-N-tert-butanesulfinyl-substituted imidates across N-sulfonyl aldimines resulted in the efficient and anti-stereoselective synthesis of new beta-(sulfonylamino)-N-sulfinyl imidates (dr > 99:1). These compounds were then successfully cyclized to give 2-aryl-N-sulfonylpiperidine-3-(N-sulfinyl) carbimidates in high yields. These proved to be useful intermediates for the synthesis of chiral methyl 2-arylpiperidine-3-carboxylates as well as cis-3-amino-2-aryl-N-sulfonylpiperidines