A general, cost-effective and sustainable replacement for silver in palladium catalysed direct arylations of C(sp2)–H and C(sp3)–H bonds.

Two series of structurally related alkoxy-tethered NHC iron(II) complexes have been developed as catalysts for the regioselective hydroboration of alkenes. Significantly, Markonikov selective alkene hydroboration with HBpin has been controllably achieved using an iron catalyst (11 examples 35-90% isolated yield) with up to 37:1 branched:linear selectivity. anti-Markovnikov selective alkene hydroboration was also achieved using HBcat and modification of the ligand backbone (6 examples, 44-71% yields). In both cases, ligand design has enabled activator-free low oxidation-state iron catalysis.

An operationally simple and environmentally benign formal hydrogenation protocol has been developed using a highly abundant iron(iii) salt and an inexpensive, bench stable, stoichiometric reductant, NaBH4, in ethanol, under ambient conditions.