General Approach for the Stereocontrolled Construction of the β-Lactam Ring in Amino Acid-Derived 4-Alkyl-4-carboxy-2-azetidinones
作者:Guillermo Gerona-Navarro、M. Teresa García-López、Rosario González-Muñiz
DOI:10.1021/jo025571j
日期:2002.5.1
The first general approach toward the asymmetric synthesis of 4-alkyl-4-carboxy-2-azetidinones derived from amino acids is described. The stereoselective construction of the beta-lactam ring was achieved through base-mediated intramolecular cyclization of the corresponding N-alpha-chloroacetyl derivatives bearing (+)- or (-)-10-(N,N-dicyclohexylsulfamoyl)isoborneol as chiral auxiliary (ee up to 82%).