A method for the regioselective asymmetric aldol addition of 2-alkyl allenoates with aldehydes to provide an α- or γ-adduct depending on the aldehyde pair is reported. In most cases, except enals, a mixture of a chiral bromoborane with 2-alkyl allenoates in the presence of iPrNEt can react with aldehydes to provide efficient γ-addition products as single isomers containing axial and central chirality. On the other hand, observations indicate that enals undergo α-addition to yield highly functionalized adducts, including an α-carbon quaternary center in high levels of diastereo- and enantioselectivity.

The conventional Phillips ethylene trimerization catalyst prepared by reacting Cr(EH)3 (EH = 2-ethylhexanoate), 2,5-dimethylpyrrole (Me2C4H2NH), Et3Al, and Et2AlCl in an aromatic hydrocarbon solvent was improved to obtain a congener composed of a new chromium precursor (EH)2CrOH, (Me2C4H2N)AlEt2, and Et3Al·ClAlEt2. Reaction of CrCl3 with 3 equiv. Na(EH) in water did not generate Cr(EH)3, but unexpectedly produced (EH)2CrOH. In comparison with the erratic catalytic performance of the original Phillips system, due to the ill-defined nature of the Cr(EH)3 source (16 or 6.8 × 10(6) g per mol-Cr h depending on the source), the improved system exhibited consistently high activity (54 × 10(6) g per mol-Cr h). Reaction of (EH)2CrOH with (Me2C4H2N)AlMe2·OEt2 afforded the dimeric Cr(II)-complex (6) coordinated by (η(5)-Me2C4H2N)AlMe2(NC4H2Me2) and μ2-κ(1):η(2)-Me2C4H2N ligands. 6 provided highly active species when activated with Et3Al·ClAlEt2.

Novel Ru (2+2) rectangles were designed and synthesized by self-assembly of a new thiophene-functionalized dipyridyl BODIPY ligand, BDPS, and ruthenium(II) precursors. The complexes exhibited dose-dependent antiproliferative activities against cancer cells, in which some compounds selectively kill cancer cells. The net fluorescence due to BODIPY allowed us to visualize their location inside cancer cells. Moreover, the metalla-rectangles displayed substantial propensity to bind with biomolecules.