A Direct Preparation of N-Unsubstituted Pyrrole-2,5-dicarboxylates from 2-Azidocarboxylic Esters
作者:Dariusz Cież
DOI:10.1021/ol901637w
日期:2009.10.1
A new and easy method for synthesis of symmetric pyrrole-2,5-dicarboxylate derivatives via a simple titanium(IV)-mediated oxidative dimerization of 2-azidocarboxylic esters is described. The process involves a transformation of titanium(IV) enolates into nonisolated 2-iminoesters, which undergo an oxidative coupling and ring closure to give the aromatic pyrrole system. A mechanism, scope and limitations
Alkyl or aryl α-keto esters of primary or secondary alcohols decompose upon irradiation at 350 – 370 nm from the intermediate triplet state into aldehydes or ketones in polar, as well as apolar solvents. The use of these keto esters as delivery systems for the controlled release of perfumery aldehydes and ketones was investigated by photoirradiation in the presence of oxygen with a Xe or UV lamp, as