American Chemical Society
Browse

Cu Photoredox Catalysts Supported by a 4,6-Disubstituted 2,2′-Bipyridine Ligand: Application in Chlorotrifluoromethylation of Alkenes

Download (3.21 MB)
journal contribution
posted on 2018-10-13, 00:00 authored by Murat Alkan-Zambada, Xile Hu
Interest in base metal catalysis motivates the development of Cu-based photoredox catalysts for organic synthesis. However, only a few Cu catalysts have been applied in photoredox reactions, the majority of which contain one or two 1,10-phenanthroline ligands. Here we design a 4,6-disubstituted 2,2′-bipyridine ligand for Cu. Two heteroleptic [Cu­(N^N)­(P^P)]­[PF6] complexes, where N^N stands for the 2,2′-bipyridine ligand and P^P stands for a bisphosphine ligand, have been synthesized and characterized. They exhibit longer excited state lifetimes and higher Cu­(I)/Cu­(II) potentials compared to the most widely used Cu catalyst, [Cu­(dap)2]­Cl. The complex with Xantphos as the P^P ligand is an efficient catalyst for chlorotrifluoromethylation of terminal alkenes, especially styrenes, which had been challenging substrates for previously reported photoredox reactions. This chlorotrifluoromethylation method enables the convenient introduction of a trifluoromethyl group into organic molecules under mild conditions, which is important for medicinal chemistry.

History