Copper hydride derived from CuF(PPh3)3·2MeOH-bis[(2-diphenylphosphino)phenyl] ethersilane can reduce electron-deficient olefins selectively and efficiently.

A series of chiral, C 2 symmetric tridentate N-heterocyclic carbene precursors, containing two N-functionalized hydroxyl or alkoxyl groups, were synthesized. They were applied to catalyze the asymmetric conjugate addition of diethylzinc to cyclohex-2-enone and cyclopent-2-enone. Enantioselectivity of corresponding reactions can be accomplished with up to 76% ee, and 65% ee, respectively. Flip of major enantiomer was observed when different bases or copper sources were utilized.

Suzuki-Miyaura coupling reactions are promoted by Pd complexes ligated with C2-symmetric multi-dentate N-heterocyclic carbenes derived in situ from Pd(OAc)2 and imidazolium salts. Good to excellent yields were obtained for aryl bromides as substrates. Turnover numbers of up to 105 could be achieved with 5 × 10−4 mol% of Pd(OAc)2/1 × 10−3 mol% NHC precatalyst in 24 h.

Asymmetric Conjugate Addition to Cyclic Enone Catalyzed by Cu-NHC Complexes with C2 Symmetry. -If cyclopent-2-enone (IV) instead of cyclohex-2-enone (I) is used for the title reaction, the stereochemistry is reversed and the enantioselectivity is much lower. The ligand AAD is prepared in a three-step synthesis. - (SHAN, F.; JIANG, L.; LI*, Z.; ZHAO, D.; Chin. J. Chem. 29 (2011)