Oxidative 5-endo cyclization of enamides mediated by ceric ammonium nitrate.
[reaction: see text] Ceric ammonium nitrate 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-755,807, Quinolacticin C, and PI-091.
Clark
Andrew J
AJ
Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK. msrir@csv.warwick.ac.uk
Dell
Colin P
CP
McDonagh
John M
JM
Geden
Joanna
J
Mawdsley
Peter
P
D000577:Amides / Q000737:chemistry*; D002563:Cerium / Q000737:chemistry*; D003500:Cyclization; D007769:Lactams / Q000138:chemical synthesis*; D010084:Oxidation-Reduction
D000577:Amides; D007769:Lactams; D002563:Cerium; C004653:ceric ammonium nitrate