Nickel-catalyzed cross-coupling of O,N-chelated diarylborinates with aryl chlorides and mesylates

Practical nickel catalysis for efficient cross-coupling of O,N-chelated diarylborinates with aryl chlorides and mesylates based on air-stable yet readily activated organonickel precursor, trans-NiCl(Ph)(PPh₃)₂, and sterically unsymmetrical N-heterocyclic carbene in situ generated from imidazolium precursor with trihydrate potassium phosphate in toluene.

Metal catalyzed defunctionalization reactions

The chronological development of metal assisted defunctionalization reactions is discussed from the stoichiometric to the catalytic stage with their application in synthetic organic chemistry.

Magnetically retrievable silica-based nickel nanocatalyst for Suzuki–Miyaura cross-coupling reaction

A new magnetically recoverable silica-based nickel nanocatalyst was synthesized, characterized and applied for the first time as a catalyst in Suzuki–Miyaura cross-coupling reaction.

N-heterocyclic carbene-assisted, bis(phosphine)nickel-catalyzed cross-couplings of diarylborinic acids with aryl chlorides, tosylates, and sulfamates

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.

Heterogeneous multifunctional catalysts for tandem processes: an approach toward sustainability

The development of sustainable organometallic chemistry is one of the many challenges that chemists must address to solve environmental issues. Until now, the classical approach was to develop highly selective homogeneous catalysts for a single transformation. However, a new area of research focuses on the execution of two or more reactions in the same vessel using heterogeneous multitask catalysts. This approach results in a reduced number of operations leading to time and cost benefits. Moreover, owing to the scarcity of natural resources and the recent dramatic cost increase of these resources and metals, the development of recyclable heterogeneous catalysts is urgent. This Minireview focuses on the latest developments in tandem reactions promoted by heterogeneous multitask catalysts.