Chemistry Letters, Vol.33, No.10, 1394-1395, 2004
A cation-exchange resin promoted imino aldol reaction, leading to the synthesis of 2-isocephem and 2-oxa-isocephem
Imino aldol reaction of ketene silyl acetals with the chiral imine 1 proceeds smoothly to givebeta-amino esters in good yields with high diasetereoselectivity under the influence of a cation-exchange resin, and the subsequent functional group transformations provide a formal synthesis of 2-isocephem and 2-oxaisocephem beta-lactam antibiotics.