δ-amino β-keto esters, a designed polyfunctionalized chiral building block for alkaloid synthesis.: Asymmetric synthesis of (R)-(+)-2-phenylpiperidine and (-)-SS20846A

delta-Amino beta-keto esters 3 and 11 are designed polyfunctionalized chiral building blocks for alkaloid synthesis and are prepared in one step from the corresponding sulfinimine (N-sulfinyl imine). Concise highly enantioselective four step syntheses of 2-phenylpiperidine (7) and SS20846A (14) from 3 and 11, respectively, are described.