Sateesh Madhi

Silica Gel-Supported Cinchona Alkaloid-OsO4 Complex for Catalytic Heterogeneous Asymmetric Dihydroxylation of Olefins by H2O2 using a Titanium Silicalite-Based Coupled Catalytic System

A triple catalytic system designed for asymmetric dihydroxylation of olefins, composed of NMM and two divergent heterogeneous catalysts, titanium silicalite and silica gel-supported 1,4-bis(9-O-dihydroquinidinyl)phthalazine [SGS-(DHQD) 2 PHAL)]-OsO 4 complex relays the transport of two electrons from olefin to H 2 O 2 used as a terminal oxidant to provide chiral diols with good yields and high enantiomeric excesses in a single pot.

Heterogeneous Bifunctional Catalysts for the Synthesis of Chiral Vicinal Diols

Heterogeneous bifunctional catalysts consisting of palladate–osmate and osmate–tungstate developed by the ion exchange on quaternary ammonium salts covalently bound to resin, and their homogeneous bimetallic analogs are evaluated for the synthesis of chiral vicinal diols. The heterogeneous bifunctional catalyst (resin-PdOs) and its homogeneous analog are used in the tandem Heck-asymmetric dihydroxylation (AD) to afford diols with excellent yields and enantiomeric excesses (ees) in the presence of various co-oxidants. The other bifunctional catalyst (resin-OsW) and its homogeneous analog are used in a simultaneous asymmetric dihydroxylation-N-oxidation of a wide range of olefins to obtain chiral vicinal diols with higher yields and ees using H2O2 as terminal oxidant. The bifunctional resin catalysts are recovered quantitatively by a simple filtration and reused for a number of cycles with consistent activity.