Asymmetric synthesis of α-chloro-β-amino-N-sulfinyl imidates as chiral building blocks.

New chiral α-chloro-β-amino-N-sulfinyl imidates were synthesized in high yield and excellent diastereomeric excess via highly anti-selective Mannich-type reactions of (RS)-methyl N-tert-butanesulfinyl-2-chloroethanimidate with aromatic aldimines. The α-chloro-β-amino-N-sulfinylimidates proved to be excellent building blocks for the asymmetric synthesis of β-amino-α-chloro amides and esters, aziridine-2-carboxylic amides and esters, trans-2-aryl-3-chloroazetidines, and methyl 4-phenyloxazolidin-2-one-5-carboxylate. The obtained absolute anti-diastereoselectivity is the opposite of the stereochemical outcome observed for α-methyl-substituted imidates.