reaction proceeds in the presence of CO, thus providing a synthesis for 1,3‐oxazin‐6‐ones (see scheme; DABCO=1,4‐diazabicyclo[2.2.2]octane, DMF=N,N‐dimethylformamide). The reaction tolerates a variety of functional groups on both the aryl ring and the amide of the substrate. Initial mechanistic studies suggest the activation of the alkenylCH bond to be a key step.
Herein, we report a novel synthesis of 1,3‐oxazin‐6‐onesfrom enamides with CO2 through C—H carboxylation and one‐potcyclization. This transition‐metal‐free and redox‐neutral process features broad substrate scope, good functional group tolerance and facile product derivatization. The nucleophilic attack to CO2 from the electron‐rich alkene is demonstrated for this reaction.
Aerobic Oxidative Carbonylation of Enamides by Merging Palladium with Photoredox Catalysis
作者:Kun Liu、Minzhu Zou、Aiwen Lei
DOI:10.1021/acs.joc.6b00965
日期:2016.8.19
Intramolecular oxidative carbonylation reaction is an efficient approach for constructing heterocycles. However, stoichiometric amount of hypervalent metal salts is usually required in this transformation. Here we show an aerobic intramolecular oxidative carbonylation of enamides by combining palladium and photoredox catalysis. The dual catalytic system enables oxygen directly as oxidant, which provides