Stereoselective synthesis of beta-hydroxyallenes with multiple contiguous stereogenic centers via aldehyde addition to alpha-alkenyl-substituted zirconacyclopentenes.

A highly stereoselective methodology for the synthesis of beta-hydroxyallenes with multiple stereogenic centers including allenic axial chirality, as well as center chirality, via addition of alpha-alkenylzirconacyclopentenes to aldehyde is described. Remarkably, the reaction occurs with completely different chemoselectivity in comparison with the usual alkyl- or aryl-substituted zirconacyclopentenes; that means, the C-C bond formation occurred selectively at the alkenylic carbon substituted with phenyl or alkyl group, while in the latter cases, insertion of aldehydes into the alkyl-zirconium bond to afford seven-membered oxazirconacycles has usually been observed.

Preparation and evaluation of non-bonded hyperbranched polymer-coated columns for capillary electrophoresis.

A series of hyperbranched poly(amine-ester)s based on 1,1,1-trimethylolpropane, methyl acrylate and diethanolamine were synthesized and coated on the inner surface of the fused-silica capillaries by physical adsorption. The most effective coating was the seventh generation hyperbranched poly(amine-ester) coating, which reduced the electroosmotic flow (EOF) greatly and suppressed protein adsorption effectively. The high separation efficiencies for basic proteins were obtained and the coating had a good stability.

[The preparation of chemical-bonded hyperbranched polymer coated column for capillary electrophoresis and their application to separation of basic proteins].

A series of hyperbranched poly(amine-ester)s were synthesized using one-step and pseudo-step procedure respectively, and their molecular structures were characterized by IR, hydroxyl value and viscosity. These polymers were coated on the inner surface of the fused-silica capillaries in a chemical bonding process. The electroosmotic flow and the separation capability for basic proteins of the coated capillaries were investigated. The results demonstrated that the coating in the capillaries could greatly reduce the electroosmotic flow and effectively suppress protein adsorption in the pH range of 3-7. The separation efficiency of the coated capillary of hyperbranched poly(amine-ester)s with trimethylolpropane and pentaerythritol as the core was 10(5)/m and 10(7)/m, respectively. The separation efficiency and the stability of basic proteins on these coated capillaries were found excellent.