Polyethylene glycol (PEG-400) as an efficient and recyclable reaction medium for one-pot synthesis of polysubstituted pyrroles under catalyst-free conditions
Polyethyleneglycol (PEG) was found to be an inexpensive non-toxic and effective medium for the one-pot synthesis of highly functionalized pyrroles. Utilizing this protocol various pyrrole derivatives were synthesized in excellent yields. Environmental acceptability, low cost, high yields, and recyclability of the PEG are the important features of this protocol.
Copper-catalyzed condensation of imines and α-diazo-β-dicarbonyl compounds: modular and regiocontrolled synthesis of multisubstituted pyrroles
作者:Wei Wen Tan、Naohiko Yoshikai
DOI:10.1039/c5sc02322j
日期:——
In the presence of a copper(II) catalyst, enolizable imines bearing various N-substituents and α-diazo-β-ketoesters undergo denitrogenative and dehydrative condensation to afford highly substituted pyrroles in moderate to good yields with exclusive regioselectivity. The reaction likely involves nucleophilic addition of the imine nitrogen to a copper carbenoid, tautomerization of the resulting azomethine