Transition metal complexes bearing amino linked N-heterocyclic carbenes (NHC) were prepared and evaluated for their antiproliferative activities in human cancer cells. The optimum antiproliferative activity, observed for the gold complex 3 in U-87 MG cells, was found to involve S-phase arrest of the cell cycle. The results indicate that 3 induces apoptosis through a p53-bak pathway, a finding that could serve as a new strategy to reduce the resistance of cancer cells to p53-induced apoptosis.

We have successfully expanded the library of amino-NHCs with varying substituents on the amine group, leading to insight about the instability of NHCs arising from the intermolecular interaction of the dangling amine side-arm. However, the pendant amine plays an important role with respect to the catalytic process, resuscitating the catalytic activity of unsaturated NHC's through a synergistic effect invoked by the secondary amine. This proof of concept allows us to expand the spectrum of catalysis to C-C, as well as C-B bond formation.

Aryl addition reactions of ArTi(O‐i‐Pr)3 to aromatic, heteroaromatic, or α,β‐unsaturated ketones are described, producing tertiary alcohols in good to excellent enantioselectivities of up to 97% ee. The structure of the dititanium complex [(i‐PrO)2Ti{μ‐(S)‐BINOLate}(μ‐O‐i‐Pr)TiPh(O‐i‐Pr)2] [(S)‐4] that simultaneously bears a chiral directing ligand and a nucleophile is reported. Complex (S)‐4 possesses a pocket structure and has been illustrated as the key active species for addition reactions of both aldehydes and ketones. Mechanistic and stereochemical insights concerning addition reactions of organometallic reagents to organic carbonyls are rationalized based on the pocket structure and pocket size of (S)‐4.

Enantioselective Additions of Aryltitanium Tris(isopropoxide) to Ketones: Structure of [(i-PrO)2Ti{μ-(S)-BINOLate}(μ-O-i-Pr)TiPh(O-i-Pr)2], Study of Mechanistic and StereochemicalInsights. -The simple title reaction affords a wide range of different substituted tertiary alcohols. -(WU, K.-H.; KUO, Y.-Y.; CHEN, C.-A.; HUANG, Y.-L.; GAU*, H.-M.; Adv. Synth. Catal. 355 (2013) 5, 1001-1008, http://dx.doi.org/10.1002/adsc.201200672 ; Dep. Chem., Natl. Chung Hsing Univ., Taichung 402, Taiwan; Eng.) -M. Zastrow 32-068