Vinyl triflates of α-keto esters react smoothly with primary amines to provide aziridinecarboxylates in good yields. In all cases, little or no stereoselectivity was observed. A mechanistic study has shown that aziridinecarboxylates are strictly formed under kinetic control. The origin of this lack of stereoselectivity is explained by a non- or poorly stereoselective proton transfer.
A Novel Approach to a Precursor of the Carbapenem Antibiotic PS-5 via Aziridine Stereospecific Carbonylation
作者:Paolo Davoli、Fabio Prati
DOI:10.3987/com-00-8974
日期:——
Cobalt cartonyl-catalyzed carbonylative ring expansion of optically pure cis-1-benzyl-3-ethyl-2-hydroxymethylaziridine (5) to trans-beta -lactam (8) afforded a key precursor of the carbapenem antibiotic (+)-PS-5. Aziridine (5) was obtained in both enantiomerically pure forms by Amano PS lipase-catalyzed esterification in n-hexane using vinyl acetate as acyl donor. The stereochemical pathway of the carbonylation reaction was proved by configurational assignments through chemical correlation.