Asymmetric synthesis of alpha-alkylated N-sulfinyl imidates as new chiral building blocks.
Alpha-alkylation of N-sulfinyl imidates, prepared via condensation of tert-butanesulfinamide with ortho esters, led to alpha-substituted N-sulfinyl imidates in good-to-excellent diastereomeric ratios (dr up to >99:1) and yields. Deprotection of the alkylated N-sulfinyl imidates gave access to the corresponding imidate hydrochlorides in outstanding yields. These imidate hydrochlorides proved to be excellent intermediates for an easy transformation to chiral amides in good yields and enantiomeric excess upon simple heating in chloroform. Hydrolysis of the alpha-benzylated imidate hydrochlorides afforded the corresponding chiral esters with >95% ee.
Department of Organic Chemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
Filip
F
Colpaert
Sven
S
Mangelinckx
Guido
G
Verniest
Norbert
N
De Kimpe
D000478:Alkylation; D000577:Amides / Q000737:chemistry; D006868:Hydrolysis; D007096:Imidoesters / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D013237:Stereoisomerism
D000577:Amides; D007096:Imidoesters