Selective Co/Ti Cooperatively Catalyzed Biaryl Couplings of Aryl Halides with Aryl Metal Reagents
摘要:
Various aryl bromides or chlorides, including those bearing a free COOH, OH, CONHR, and SO2NHR group, coupled with aryl magnesium or lithium reagents in the presence of 7.5 mol % CoCl2/15 mol % PBu3 and substoichiometric Ti(OEt)(4) (40 mol % to ArM) at room temperature in high yields with high chemo- and regioslectivity. This simple reaction represents the first example of Co/Ti cooperative catalysis which plays a key role in suppressing undesired homocouplings.
Cobalt-Catalyzed Biaryl Couplings via C–F Bond Activation in the Absence of Phosphine or NHC Ligands
作者:Juan Wei、Kun-Ming Liu、Xin-Fang Duan
DOI:10.1021/acs.joc.6b02354
日期:2017.2.3
Co-catalyzed biaryl coupling through C–F cleavage under phosphine or NHC-free conditions was described. A broad range of aryl fluorides including unactivated fluorides as well as those with sensitive functionalities could couple with various Ti(OEt)4-mediated aryl Grignard reagents with high selectivity under the catalysis of CoCl2/DMPU. Importantly, selective C–F bond activationcouplings between two types