Manganese is a non‐toxic, inexpensive and earth abundant metal, so is a perfect candidate for catalysis whether as a replacement for precious metals or in the search for novel reactivity. Despite this, manganese catalysis has not undergone the same development of other earth‐abundant metals (particularly iron and cobalt). This review details recent synthetic methodologies using manganese catalysts, including C–H activation, late stage fluorination, hydrosilylation and cross‐coupling.

The manganese-catalyzed hydrosilylation and hydroboration of alkenes has been developed using a single manganese(II) precatalyst and reaction protocol. Both reactions proceed with excellent control of regioselectivity and in high yields across a variety of sterically and electronically differentiated substrates (25 examples). Alkoxide activation, using NaO Bu, was key to precatalyst activation and reactivity. Catalysis was achieved across various functional groups and on gram-scale for both the developed methodologies with catalysts loadings as low as 0.5 mol %.

Simple, commercially available borane adducts, H3B·THF and H3B·SMe2, have been used to catalyse the hydroboration of alkynes and alkenes with pinacolborane to give the alkenyl and alkyl boronic esters, respectively. Alkynes and terminal alkenes underwent highly regioselective hydroboration to give the linear boronic ester products. Good functional group tolerance was observed for substrates bearing ester, amine, ether and halide substituents. This catalytic process shows comparable reactivity to transition-metal-catalysed hydroboration protocols.

Two novel succinimide-based palladium complexes, AsCat and FurCat, are highly efficient catalysts for room-temperature Stille cross-coupling of organostannanes with benzyl chlorides. The air- and moisture-stable catalysts are prepared in one step, and the coupling reactions proceed with a high selectivity for the benzyl position under mild conditions without the need for additives.

The manganese-catalyzed hydrosilylation and hydroboration of alkenes has been developed using a single Mn(II) pre-catalyst and reaction protocol. Both reactions proceed with excellent control of regioselectivity in high yields across a variety of sterically and electronically differentiated substrates (25 examples). Alkoxide activation, using NaO t Bu, was key to pre-catalyst activation and reactivity. Catalysis was achieved across various functional groups and on gram-scale across both the developed methodologies with catalysts loadings as low as 0.5 mol%.

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Succinimide--based palladium complex catalysts with either triphenylarsenic or trifuranylphospine ligands are used for the coupling of organostannanes with benzyl halogenides at ambient temperature. Depending on the stannane substituents one of the catalysts furnishes the products in good yields. Both novel catalysts exhibit a remarkable activity in the Stille cross-coupling of benzyl chlorides at room temperature and show a useful selectivity for benzyl chlorides over aryl bromides. -(RONSON, T. O.; CARNEY, J. R.; WHITWOOD, A. C.; TAYLOR, R. J. K.; FAIRLAMB*, I. J. S.; Chem. Commun. (Cambridge) 51 (2015) 16, 3466-3469, http://dx.