A pivaloyl functionalized chitosan biopolymer was used as a polyligand for the [Ru(p-cymene)Cl2] moiety. The functionalized biopolymer containing a metal to saccharide ratio of 0.33 was used as a catalyst for the asymmetric transfer hydrogenation of ketones. The reactions gave yields up to 80% 65 65
Using a high-throughput experimental procedure, a series of cobalt(iii) complexes of the general formula CpRCo(I)(X)(L) were prepared and screened for their activity towards the catalytic nucleophilic fluorination of benzoyl chloride.
High-throughput screening and lab-scale optimization were combined to develop the catalytic system trans-RuCl((S,S)-skewphos)((R,R)-dpen), 2-PrONa, and 2-PrOH. This system hydrogenates functionalized α-phenoxy and related amides at room temperature under 4 atm H pressure to give chiral alcohols with up to 99% yield and in greater than 99% enantiomeric excess via dynamic kinetic resolution.
The successful stereocontrol of the Diels-Alder reaction of semicyclic dienes possessing a secondary and tertiary allylic magnesium alkoxide alcohol functionality and activated dienophiles such as methyl acrylate, methacrolein, acrolein, and N-phenylmaleimide is described.
The development of selective and robust heterogeneous oxidation catalysts is an enabling technology for conversion of biomass-derived platform chemicals. Vanadium active sites were incorporated into the structure of mesoporous silica via an ultra-fast, one-pot synthesis method based on microwave-assisted heating. In addition, Al/Ti/Zr/Ce anchoring ions were introduced in order to minimize vanadium leaching and better control its dispersion. The supported V-(Al/Ti/Zr/Ce)-MCM-41 composite materials were assessed as catalysts for aerobic C–C bond cleavage of simple models for lignin (1,2-diphenyl-2-methoxyethanol) and sugar-derived polyalcohols (meso-hydrobenzoin). The TiIV ions proved to be the best anchors to prevent V leaching, while AlIII and ZrIV ions were the best to improve selective conversion of the substrates. The active sites in these catalysts are shown to be 2D VOx layers stabilized on the anchors. In a screen of twelve solvents, weakly polar solvents like toluene were found to be most suitable for this reaction, as was environmentally friendly ethyl acetate. The above properties, together with the high selectivity for C–C bond cleavage, advocate for a heterogeneous catalytic pathway, intrinsically different from that reported previously for molecular oxovanadium (V) catalysts.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.