An operationally convenient and general method for hydroboration of alkenes, aldehydes, and ketones employing Co(acac) 3 as a precatalyst is reported. The hydroboration of alkenes in the presence of HBpin, PPh 3 , and NaO t Bu affords good to excellent yields with high Markovnikov selectivity with up to 97:3 branched/linear selectivity. Moreover, Co(acac) 3 could be used effectively to hydroborate aldehydes and ketones in the absence of additives under mild reaction conditions. Inter-and intramolecular chemoselective reduction of the aldehyde group took place over the ketone functional group.

Iron complexes [BIAN]Fe(I)(η6‐toluene) (M1) and [BIAN]FeCl2 (M2) (BIAN=bis(2,6‐diisopropylaniline)acenaphthene) were found to be viable catalysts for the regioselective hydroboration of alkynes and alkenes. The hydroboration of alkynes and alkenes in the presence of HBpin and an activator at 70 °C afforded linear vinyl and alkyl boronic esters, respectively. Selectivity up to 98% was observed for alkyl boronic esters and exclusive formation of trans product was observed for vinyl boronic esters.

Hydrosilylation is a fundamental organometallic transformation for the reduction of alkene, carbonyl, and imine functionalities. Herein, we use density functional theory (DFT) calculations, supplemented by experiments, to propose and explore two possible reaction mechanisms of iron(0)-catalyzed hydrosilylation of aldehydes: One is initiated via hydrogen transfer from silane to benzaldehyde, and the other is initiated via σ-bond metathesis between Si–H and Fe–O bonds. The former mechanism is favored owing to the much lower calculated activation energy. In addition, spin crossover is expected to occur in this low-valent iron(0)-catalyzed reaction and is verified by different computational methods, which indicates that this reaction should have two-state reactivity (TSR). Hence, the reaction along the favored pathway is proposed to take place via quintet intermediates and triplet transition states before the generation of the final product, silyl ether. This study will be helpful for understanding reaction mechanisms involving iron catalysts and may provide a new insight on the design of new iron catalysts by careful tuning of the electronic structure of ligands.

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