Triazoles from N-Alkynylheterocycles and Their Coordination to Iridium
摘要:
N-alkynylheterocycles (benzimidazole and indazole) are converted to triazoles by click chemistry, and the resulting triazoles react with [IrCl2Cp*](2). The benzimidazole-triazole coordinates in a monodentate fashion through the benzimidazole, whereas the indazole-triazole is bidentate through coordination of both heterocycles. Reaction of the benzimidazole-triazole with methyliodide gives a benzimidazolium salt that deprotonates on coordination to afford a rare example of a bidentate NHC-triazole.
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.