Cu-Catalyzed N-Alkynylation of Imidazoles, Benzimidazoles, Indazoles, and Pyrazoles Using PEG as Solvent Medium
摘要:
A facile and efficient Cu(I)-catalyzed cross-coupling method is reported for the preparation of N-alkynyl or N-bromoalkenyl heteroarenes from bromoalkynes. Generally superior yields and functional group tolerance were obtained with microwave (MW) irradiation using imidazole, benzimidazole, pyrazole, and indazole substrates and poly(ethylene glycol) 400 (PEG400) as an additive. We speculate that PEG400 acts as both a Cu(I)-stabilizing ligand as well as a phase transfer solvent.
Cu-Catalyzed N<i>-</i>Alkynylation of Imidazoles, Benzimidazoles, Indazoles, and Pyrazoles Using PEG as Solvent Medium
作者:Glenn A. Burley、David L. Davies、Gerry A. Griffith、Michael Lee、Kuldip Singh
DOI:10.1021/jo902466f
日期:2010.2.5
A facile and efficient Cu(I)-catalyzed cross-coupling method is reported for the preparation of N-alkynyl or N-bromoalkenyl heteroarenes from bromoalkynes. Generally superior yields and functional group tolerance were obtained with microwave (MW) irradiation using imidazole, benzimidazole, pyrazole, and indazole substrates and poly(ethylene glycol) 400 (PEG400) as an additive. We speculate that PEG400 acts as both a Cu(I)-stabilizing ligand as well as a phase transfer solvent.