A dibenzobarrelene-bridged, α-diimine Ni(II) catalyst (rac-3) was synthesized and shown to have exceptional behavior for the polymerization of ethylene. The catalyst afforded high molecular weight polyethylenes with narrow dispersities and degrees of branching much lower than those made by related α-diimine nickel catalysts. Catalyst rac-3 demonstrated living behavior at room temperature, produced linear polyethylene (Tm =135 °C) at -20 °C, and, most importantly, was able to copolymerize ethylene with the biorenewable polar monomer methyl 10-undecenoate to yield highly linear ester-functionalized polyethylene.

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Phenols can be employed as proelectrophiles in operationally simple ruthenium-catalyzed dehydrative direct arylations, proceeding through chemo- and regioselective functionalizations of C-H and C-OH bonds.

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A new carbonylation catalyst is reported that provides enantioenriched b-lactones and aldol-type products from the carbonylative ring-expansion of racemic cis-epoxides. Detailed analysis of the reaction demonstrates that the epoxide substrates undergo regiodivergent carbonylation reactions instead of traditional kinetic resolutions. This new catalytic system was applied to the synthesis of a key fragment of the antibiotic Globomycin.Scheme 1 Approaches to enantioenriched anti-aldol adducts and trans-b-lactones.