The primary insertion (or 1,2-insertion) of propylene into (C 5 Me 5 ) 2 YCH 2 CH 2 CH(Me) 2 , as well as the primary and secondary (or 2,1) insertions of propylene into the activated ansa-zirconocene complex [{Ph(H)C-(3,6-tBu 2 Flu)(3-tBu-5-Me-C 5 H 2 )}ZrMe] + were calculated with several DFT methods to find the most adequate methodology for the computation of metallocene-catalyzed olefin polymerization reactions. For the yttrium system, both solvent corrections and dispersion corrections are needed to determine energies of coordination and activation barriers in agreement with experimental data. Dispersion corrections were included directly via the use of specific functionals like B97D and M06 or were added as empirical corrections (GD3BJ) to the B3PW91 calculations. For the zirconocene system, the best method is a combination of B3PW91 with solvent corrections incorporated with the SMD continuum model. The dispersion corrections, included via both GD3BJ and M06, tend to overestimate the stabilization of the adducts because of the high steric bulk of the zirconocene system. The addition of dispersion corrections shifts the energy profiles toward lower values but does not affect the relative activation barriers. Implementation of entropy corrections counterbalances almost perfectly the dispersion corrections. The same observations arise from the study of the C−H activations of propylene induced by the zirconocene complex.

[Structure: see text] An efficient catalytic system for the three-component coupling of electrophilic alkenes, aldehydes, and silane was optimized with a new family of copper N-heterocyclic carbene complexes. These catalysts do not require activation and show high activity (TOF>15,000 h-1) as well as some anti diastereoselectivity.

Efficient fragmentation of catalyst particles during the polymerization of olefins is a necessary process to maintain catalyst activity and obtain discrete polymer particles with ideal density and morphology. Collecting experimental...

To be or not to bifluoride: Two synthetic pathways to unprecedented N-heterocyclic carbene copper(I) bifluoride complexes have been developed. Catalytic tests demonstrated that copper(I) bifluorides are very efficient catalysts, which do not require any additional activating agent. The first Cu-catalyzed diastereoselective allylation of (R)-N-tert-butanesulfinyl aldimines was also established. The method enables efficient, simple and general synthesis of enantiomerically enriched homoallylic amines at room temperature in high yields.