An expanded family of ruthenium metathesis catalysts bearing cyclic alkyl amino carbene (CAAC) ligands is reported. These catalysts exhibited exceptional activity in the ethenolysis of the seed oil derivative methyl oleate. In many cases, TONs >100,000 were achieved, at only 3 ppm catalyst loading. Remarkably, the most active catalyst system was able to achieve a TON of 340,000, at only 1 ppm catalyst loading. This is the first time a series of metathesis catalysts has exhibited such high performance in cross metathesis reactions employing ethylene gas, with activities sufficient to render ethenolysis applicable towards the industrial scale production of linear alpha-olefins (LAOs) and other terminal olefin products.

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Two (cAAC)2Cu complexes, featuring a two-coordinate copper atom in the formal oxidation state zero, were prepared by reducing (Et2-cAAC)2Cu(+)I(-) with metallic sodium in THF, and by a one-pot synthesis using Me2-cAAC, Cu(II)Cl2, and KC8 in toluene in a molar ratio of 2:1:2, respectively. Both complexes are highly air and moisture sensitive but can be stored in the solid state for a month at room temperature. DFT calculations showed that in these complexes the copper center has a d(10) electronic configuration and the unpaired electron is delocalized over two carbene carbon atoms. This was further confirmed by the EPR spectra, which exhibit multiple hyperfine lines due to the coupling of the unpaired electron with (63,65)Cu isotopes, (14)N, and (1)H nuclei.

** Mr. Lawrence M. Henling is acknowledged for X-ray crystallography analysis. Dr. David VanderVelde is thanked for assistance with NMR experiments. Thay Ung, Dr. Daryl P. Allen, and Dr. Richard L. Pederson (Materia Inc.) are thanked for helpful discussions regarding initial experimentation and setup.

We report the first structurally characterized terminal Ce(III) acetylide complex, Na[Ce(CCPh)-(bdmmp) 3 ] (2), isolated from the salt metathesis of NaC CPh with Na[Ce(OTf)(bdmmp) 3 ] (1; bdmmp − = 2,6-bis-(dimethylamino)-4-methylphenolate). Compound 2 inserted acetophenone to form the tertiary alkoxide complex Na[Ce-(OC(Me)(Ph)CCPh)(bdmmp) 3 ] (4), rather than forming an enolate product. To the best of our knowledge, complexes 2 and 4 are the first structurally characterized products that exhibit carbonyl group insertion into a Ce−C bond, affording new information on an important class of organocerium reagents.C erium compounds have been used extensively in organic transformations of carbonyl substrates in carbon−hydrogen or carbon−carbon bond forming reactions, including the conversion of ketones to tertiary alcohols. 1,2 Due to their nonbasic nucleophilicity, these cerium-driven reductions occur selectively, even for ketones that readily undergo enolization or pinacol coupling (Scheme 1).