Chan-Lam cross-coupling reaction based on the Cu 2 S/TMEDA system

Abstract A catalyst based on the readily available Cu 2 S/TMEDA system using a stable copper(I) source was developed for the Chan-Lam cross-coupling reaction. The capability of the catalyst was demonstrated with 1 H -benzo[ d ]imidazol-2(3 H )-one, 1 H -benzo[ d ]imidazole, and 1 H -imidazole together with electron-deficient, electron-rich, and sterically demanding boronic acids at room temperature in the presence of atmospheric oxygen to give the cross-coupling products in moderate to excellent yields. In addition, the coupling reaction of 1 H -benzo[ d ]imidazole with several pinacol or neopentylglycol boronates indicated further potential of the catalyst. The reaction conditions tolerate the hydroxyl and bromo functional groups. The catalytic system also enables to synthesize the mono-N-substituted anilines from primary aliphatic amines. However, the two model compounds for the secondary and aromatic amines, piperidine and aniline, do not react. Two sterically demanding products with the restricted C N bond rotation, synthesized by the N -arylation of 1 H -benzo[ d ]imidazol-2(3 H )-one with o -tolylboronic acid, enabled to confirm the atropisomers prepared by the Chan-Lam cross-coupling reaction. Furthermore, an example of one-pot Chan-Lam and Suzuki-Miyaura reaction has been reported.