Asymmetric synthesis of new chiral β-amino acid derivatives by Mannich-type reactions of chiral N-sulfinyl imidates with N-tosyl aldimines

摘要

New chiral beta-(sulfonylamino)sulfinylimidates are synthesized in high overall yield and excellent diastereomeric excess via highly anti-selective Mannich-type reactions of chiral N-tert-butanesulfinyl imidates with N-tosyl aldimines. Deprotection of the beta-(sulfonylamino)sulfinylimidates gave access to enantiopure imidate hydrochlorides in high yields, as useful intermediates for an easy transformation to new chiral beta-sulfonylamino amides upon simple heating in chloroform. Hydrolysis of the imidate hydrochlorides afforded the corresponding chiral beta-sulfonylamino esters with >98% ee as new chiral beta-amino acid derivatives.