M. S. Sarkar

Asymmetric dihydroxylation catalyzed by SBA-15 silica-supported bis-cinchona alkaloid

Abstract MCM-supported bis-cinchona alkaloid complexed to osimium was examined as a chiral catalyst in asymmetric dihydroxylation of olefins. The desired diols were obtained in high yield with high enantiomeric excesses of up to 99%. High ordered MCM-41 silica was found to be better inorganic support for the catalytic system than amorphous silica gel.

Highly efficient microwave-assisted asymmetric transfer hydrogenation with SBA-15-supported TsCHDA chiral ligands

A fast and efficient procedure has been developed for microwave-assisted asymmetric transfer hydrogenation of ketones. The reactions were brought to full conversion in short time using SBA-15-supported TsCHDA chiral ligands.

Mesoporous silica SBA-15-supported palladium catalyst for green Sonogashira coupling reactions

We have immobilized diphosphane palladium onto mesoporous SBA-15 silica. The immobilized Pd complex was used as a highly effective catalyst for Sonogashira coupling reaction. Excellent conversions as well as high reactivities have been observed in 1 h for the Sonogashira couplings of aryl halides.

VO(acac)2 incorporated in mesoporous silica SBA-15-confined ionic liquid as a catalyst for epoxidation

VO(acac) 2 was incorporated with the aid of ionic liquid onto mesoporous silica SBA-15 material. The immobilized VO(acac) 2 was used as an effective catalyst for epoxidation of allylic alcohols.

Mesoporous silica-SBA-15 supported N-heterocyclic carbene-Pd complex for Suzuki coupling reaction

N-Heterocyclic carbene-Pd complex was anchored on mesoporous silica SBA-15 material. The heterogenized Pd complex was employed as a highly effective catalyst for Suzuki cross-coupling reaction under aqueous conditions. The catalyst was reusable without a significant loss of catalytic activity as well as air-stable and thermally stable to allow easy use.

Microwave-assisted heterogeneous transfer hydrogenation of ketones

A first and efficient procedure has been developed for microwave-assisted transfer hydrogenation of ketones. Silica gel-supported ligand 2 has been prepared for the transfer hydrogenation. This immobilized ligand-Ru complex acted as an efficient catalyst for the hydrogen transfer reaction of ketones. The MW-assisted reactions using the supported ligand 2 could reach completion within 20~40 min.

Mesoporous silica-supported chiral norephedrine ligands for asymmetric transfer hydrogenation

Optically active norephedrine was anchored on three different mesoporous silica materials. The immobilized norephedrines could be served as enantioselective ligands in the asymmetric transfer hydrogenation of ketones. The heterogeneous catalysts gave satisfactory enantioselectivity as well as high levels of catalytic activity in the transfer hydrogenation.

Heterogeneous asymmetric transfer hydrogenation with mesoporous silica SBA-15-supported Ru-TsCHDA catalyst

Chiral TsCHDA was successfully anchored on SBA-15 silica material. The mesoporous system was used as an efficient heterogeneous chiral ligand in the asymmetric transfer hydrogenation of ketones.