Organoboron reagents represent a unique class of compounds because of their utility in modern synthetic organic chemistry, often affording unprecedented reactivity. The transformation of the carbon−boron bond into a carbon−X (X = C, N, and O) bond in a stereocontrolled fashion has become invaluable in medicinal chemistry, agrochemistry, and natural products chemistry as well as materials science. Over the past decade, first-row dblock transition metals have become increasingly widely used as catalysts for the formation of a carbon−boron bond, a transformation traditionally catalyzed by expensive precious metals. This recent focus on alternative transition metals has enabled growth in fundamental methods in organoboron chemistry. This review surveys the current state-of-the-art in the use of first-row d-block element-based catalysts for the formation of carbon−boron bonds.

The first example of a Cu-catalysed borylation of a wide range of aryl chlorides with different electronic and steric properties is mediated by a readily prepared NHC-stabilised Cu catalyst and KOtBu. The aryl chlorides are converted into their corresponding arylboronic esters using B2pin2 or B2neop2 as the boron reagent.

We report herein the room temperature insertion of the carbene carbon atom of the cyclic (alkyl)(amino) carbene cAAC into the B-B single bonds of the diboron(4) compounds Bpin, Bcat, Bneop, and Beg (pin = pinacolato, cat = catecholato, neop = neopentylglycolato, eg = ethyleneglycolato).

The complexes trans-[Ni(iPr 2 Im) 2 Br 2 ] 1, trans-[Ni-(iPr 2 Im Me ) 2 Br 2 ] 2, trans-[Ni(Me 2 Im) 2 I 2 ] 3, and trans-[Ni-(Me 2 Im Me ) 2 Br 2 ] 4 (R 2 Im = 1,3-diorganyl-imidazolin-2-ylidene, R 2 Im Me = 1,3-diorganyl-4,5-dimethyl-imidazolin-2-ylidene) are useful precursor for the synthesis of NHC-stabilized nickel olefin, alkyne, alkyl and cyanido complexes. [Ni(NHC) 2 (η 2 -olefin)] and [Ni(NHC) 2 (η 2 -alkyne)] can be prepared via metallic reduction in the presence of the olefin or alkyne, as exemplified by the synthesis of [Ni(Me 2 Im) 2 (η 2 -C 2 H 4 )] 5, [Ni(Me 2 Im) 2 (η 2 -C 2 Me 2 )] 6, [Ni(Me 2 Im) 2 (η 2 -COE)] 7 and [Ni(Me 2 Im Me ) 2 (η 2 -COE)] 8 (COE = [a]

NHC-nickel( NHC = N-heterocyclic carbene) complexes are efficient catalysts for the CÀCl bond borylation of aryl chlorides using NaOAc as ab ase and B 2 pin 2 (pin = pinacolato) as the boron source.T he catalysts [Ni 2 (ICy) 4 (m-(h 2 :h 2 )-COD)] (1,I Cy = 1,3-dicyclohexylimidazolin-2-ylidene;C OD = 1,5-cyclooctadiene), [Ni(ICy) 2 (h 2 -C 2 H 4 )] (2), and [Ni(ICy) 2 (h 2 -COE)] (3,C OE = cyclooctene) comparew ell with other nickel catalysts reported previously for aryl-chloride borylation with the advantage that no further ligandsh ad to be added to the reaction. Borylation also proceeded with B 2 neop 2 (neop = neopentylglycolato)a st he boron source. Stoichiometrico xidative addition of different aryl chlorides to complex 1 was highly selectivea ffording trans-[Ni(ICy) 2 (Cl)(Ar)]

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Fluoride ion plays a dual role in both metal-catalysed and metal-free borylation reactions by activating B2pin2 and trapping Lewis acidic FBpin.