893738-92-6Relevant articles and documents
Palladium-catalyzed cross-coupling of aryl chlorides with O, N-chelate stabilized diarylborinates
Zhang, Nan,Wang, Chen,Zou, Gang,Tang, Jie
supporting information, p. 54 - 58 (2017/05/15)
A series of O, N-chelated diarylborinates have been prepared and tested as arylboron counterpart alternative to oxygen-labile diarylborinic acids in palladium catalyzed Suzuki coupling of aryl chlorides. 3-Dimethylaminopropyl diarylborinates (B-5a), featuring a six-membered O, N-chelated boron ring that was confirmed by single crystal X-ray diffraction, displayed a delicately balanced stability and reactivity. Their cross-coupling with structurally various aryl chlorides could be effected as efficiently as that of the parent diarylborinic acids by using 0.1～1mol% Pd(OAc)2/IPr/P(OPh)3 as catalyst system, to provide the corresponding biaryls in good to excellent yields.
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 (2014/08/18)
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.
