Nickel-Catalyzed α-Alkylation of Arylacetonitriles with Challenging Secondary Alcohols.

Nickel(II) complex 1 was utilized as a sustainable catalyst for α-alkylation of arylacetonitriles with challenging secondary alcohols. Arylacetonitriles with a wide range of functional groups were tolerated, and various cyclic and acyclic secondary alcohols were utilized to yield a large number of α-alkylated products. The plausible mechanism involves the base-promoted activation of precatalyst 1 to an active catalyst 2 (dehydrochlorinated product) which activates the O-H and C-H bonds of the secondary alcohol in a dehydrogenative pathway.

Cobalt-Catalyzed Chemodivergent Synthesis of Cyclic Amines and Lactams from Ketoacids and Anilines Using Hydrosilylation.

Here, commercially available Co2(CO)8 was utilized as an efficient catalyst for chemodivergent synthesis of pyrrolidines and pyrrolidones from levulinic acid and aromatic amines under slightly different hydrosilylation conditions. 1.5 and 3 equiv of phenylsilane selectively yielded pyrrolidone and pyrrolidine, respectively. Various ketoacids and amines were successfully tested. Plausible mechanism involves the condensation of levulinic acid and amine to form an imine, which cyclizes to 3-pyrrolidin-2-one followed by reduction to pyrrolidone. The final reduction of pyrrolidone gave pyrrolidine.

Cobalt catalyzed chemoselective reduction of nitroarenes: hydrosilylation under thermal and photochemical reaction conditions.

Commercially available Co2(CO)8 was used as an effective catalyst for the hydrosilylation of nitroarenes under both thermal and photochemical conditions. A wide variety of nitroarenes with various functionalities were selectively reduced to aromatic amines. Syntheses of drug molecules expand the potential utility of this protocol. Experimental evidence suggested a radical pathway.