An assortment of aromatic ketones was successfully functionalized with a variety of unactivated secondary alcohols that serve as alkylating agents, providing β-disubstituted ketone products in good to excellent yields. Remarkably, challenging substrates such as simple acetophenone derivatives are effectively alkylated under this ruthenium catalysis. The substituted cyclohexanol compounds displayed product-induced diastereoselectivity. Mechanistic studies indicate the involvement of the hydrogen-borrowing pathway in these alkylation reactions. Notably, this selective and catalytic C− C bond-forming reaction requires only a minimal load of catalyst and base and produces H 2 O as the only byproduct, making this protocol attractive and environmentally benign.

Alcohols and nitrile functionalities have widespread applications in biochemical and chemical synthesis. Catalytic transformations involving C−C bond formation relying on unsaturated coupling partners create important pathways for processes in synthetic, material, and medicinal chemistry. The discovery of a simple and selective coupling of nitriles with allylic alcohols catalyzed by a ruthenium pincer complex is described, which tolerates reactive functional groups such as carbamate, sulfonate, olefin, cyano, and trifluoromethyl-substituted benzyl nitriles. Homo allylic alcohols also provided 1,4-addition products following the isomerization of double bonds. Mechanistic studies supported that the allylic alcohols initially undergo selective oxidation by the catalyst to α,β-unsaturated carbonyl compounds followed by 1,4-conjugate addition of benzyl nitriles catalyzed by a base and subsequent catalytic reduction of carbonyl functionality, leading to the formation of δ-hydroxynitrile products. The catalytic cycle of this tandem process is established by density functional theory studies. Remarkably, anipamil drug is successfully synthesized using this catalytic protocol. The utility of the δ-hydroxynitrile products in the synthesis of biologically active molecules and their further functionalization are also demonstrated.

Organoborane-catalyzed hydroboration of nitriles provides N,N-diborylamines, which act as efficient synthons for the synthesis of primary amines and secondary amides. Known nitrile hydroboration methods are dominated by metal catalysis. Simple and metal-free hydroboration of nitriles using diborane [H-B-9-BBN]2 as a catalyst and pinacolborane as a turnover reagent is reported. The reaction of monomeric H-B-9-BBN with nitriles leads to the hydrido-bridged diborylimine intermediate; a subsequent sequential double hydroboration-transborylation pathway involving B-N/B-H σ bond metathesis is proposed.

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