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.

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]

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).

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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.