Oxidative 5-<i>Endo</i> Cyclization of Enamides Mediated by Ceric Ammonium Nitrate
作者:Andrew J. Clark、Colin P. Dell、John M. McDonagh、Joanna Geden、Peter Mawdsley
DOI:10.1021/ol030045f
日期:2003.6.1
[reaction: see text] Cericammoniumnitrate mediates the oxidative 5-endo radical-polar crossover reactions of beta-enamide esters to give 5,5-C,O-disubstituted-gamma-lactams. Trapping of the intermediate cations leads to 5-hydroxy- or 5-alkoxy-gamma-lactams depending upon the reaction conditions. The methodology was used to synthesize the basic heterocyclic ring fragments of the natural products L-755