1519010-67-3Relevant academic research and scientific papers
N-heterocyclic carbene-assisted, Bis(phosphine)nickel-catalyzed cross-couplings of diarylborinic acids with aryl chlorides, tosylates, and sulfamates
Ke, Haihua,Chen, Xiaofeng,Zou, Gang
, p. 7132 - 7140 (2014)
Efficient bis(phosphine)nickel-catalyzed cross-couplings of diarylborinic acids with aryl chlorides, tosylates, and sulfamates have been effected with an assistance of N-heterocyclic carbene (NHC) generated in situ from N,N′-dialkylimidazoliums, e.g., N-butyl-N′-methylimidazolium bromide ([Bmim]Br), in toluene using K3PO4·3H2O as base. In contrast to bis(NHC)nickel-catalyzed conventional Suzuki coupling of arylboronic acids, mono(NHC)bis(phosphine)nickel species generated in situ from Ni(PPh3)2Cl2/[Bmim]Br displayed high catalytic activities in the cross-couplings of diarylborinic acids. The structural influences from diarylborinic acids were found to be rather small, while electronic factors from aryl chlorides, tosylates, and sulfamates affected the couplings remarkably. The couplings of electronically activated aryl chlorides, tosylates, and sulfamates could be efficiently effected with 1.5 mol % NiCl2(PPh3)2/[Bmim]Br as catalyst precursor to give the biaryl products in excellent yields, while 3-5 mol % loadings had to be used for the couplings of non- and deactivated ones. A small ortho-substitutent on the aromatic ring of aryl chlorides, tosylates, and sulfamates was tolerable. Applicability of the nickel-catalyzed cross-couplings in practical synthesis of fine chemicals has been demonstrated in process development for a third-generation topical retinoid, Adapalene.
Nickel-catalyzed cross-coupling of diarylborinic acids with aryl chlorides
Chen, Xiaofeng,Ke, Haihua,Zou, Gang
, p. 379 - 385 (2014/03/21)
A highly efficient nickel/triarylphosphine catalyst system, Ni[P(4-MeOPh)3]2Cl2/2P(4-MeOPh)3, has been developed for cross-coupling of diarylborinic acids with a wide range of aryl chlorides. A variety of unsymmetrical biaryl and heterobiaryl compounds with various functional groups and steric hindrance could be obtained in good to excellent yields using 0.5-2 mol % catalyst loadings in the presence of K 3PO4·3H2O in toluene. The high atom economy of diarylborinic acids and cost-effectiveness of the nickel/phosphine catalyst system make the cross-coupling truly practical in the production of biaryl fine chemicals. Usefulness of the nickel/phosphine catalyzed cross-coupling of diarylborinic acids with aryl chlorides has been demonstrated in the development of a scalable and economical process for synthesis of 4′-methyl-2-cyanobiphenyl, Sartan biphenyl.
