Polycondensation catalyzed by polyvinyl pyrrolidone‐supported metal complexes

Enantioselective cyclizations of silyloxyenynes catalyzed by cationic metal phosphine complexes.

The discovery of complementary methods for enantioselective transition metal-catalyzed cyclization with silyloxyenynes has been accomplished using chiral phosphine ligands. Under palladium catalysis, 1,6-silyloxyenynes bearing a terminal alkyne led to the desired five-membered ring with high enantioselectivities (up to 91% ee). As for reactions under cationic gold catalysis, 1,6- and 1,5-silylo...

Nickel (0) Catalyzed Kumada Chain Transfer Polycondensation

Exploring chain length selectivity in HIC-catalyzed polycondensation reactions.

Polyester synthesis activity of immobilized Humicola insolens (HiC) was systematically studied with three-series of substrates varying in (i) omega-hydroxyalkanoic acid (omegaHA), (ii) alpha,omega-n-alkane diol, and (iii) alpha,omega-n-alkane diacid chain length. Covalent immobilization of HiC on Amberzyme oxirane (AO) resin (i.e., AO-HiC) was prepared. HiC-AO's activity for omegaHA substrates ...

Fast screening of polycondensation catalyst, Determination of the kinetic data of catalyzed polycondensation in polyethylene terephthalate synthesis

Differential scanning calorimetry (DSC) belongs to the family of thermal analysis methods. In general thermal analysis is the determination of substance properties in dependence on temperature. Thermodynamic data (heat capacity, phase transition, enthalpy) and kinetic data can be determined by methods of thermal analysis. The greatest advantage of thermal analysis is the easy handling and the o...

Enantioselective reactions catalyzed by chiral pyridine 2,6-bis(5',5'-diphenyloxazoline)-metal complexes*

A new class of tridentate pyridine-bis(oxazoline) ligand having gem-diphenyl groups at C5 of the oxazoline rings has been developed. Its metal complex exhibited high catalytic efficiency in asymmetric synthesis. We have shown that gem-diphenyl groups at C5 of the oxazoline rings are essential for getting high enantiomeric excess.