Jagjit Yadav

A Click Strategy for the Immobilization of MacMillan Organocatalysts onto Polymers and Magnetic Nanoparticles

A chemically modified, first generation MacMillan imidazolidin-4-one has been anchored onto 1% DVB Merrifield resin and Fe3O4 (5.3 ± 1.4 nm) magnetic nanoparticles through copper-catalyzed alkyne azide cycloaddition (CuAAC) reactions. The resulting immobilized catalysts have been successfully used in the asymmetric Friedel-Crafts alkylation of N-substituted pyrroles with α,β-unsaturated aldehydes. The PS-supported catalyst (B) showed higher catalytic activity and enantioselectivity, while the MNP-supported one (A) showed higher recyclability and could be used in a sequential process with intermediate magnetic decantation.

A Pd(II)/Mg–La mixed oxide catalyst for cyanation of aryl C–H bonds and tandem Suzuki–cyanation reactions

A palladium(II)/magnesium–lanthanum mixed oxide (Pd(II)/Mg–La) catalyst is a reusable catalyst for cyanation of aromatic C–H bonds by using the combination of NH4HCO3 and DMSO as the ‘‘CN’’ source. Moderate to good yields of aromatic nitriles were obtained. An excellent regioselectivity was achieved using the present protocol. A tandem process involving Suzuki coupling followed by a cyanation reaction was also developed using the heterogeneous (Pd(II)/Mg–La) catalyst. This cascade process resulted in the formation of aromatic nitrile from simple 2-halopyridine. The catalyst was recovered by centrifugation and reused for three consecutive cycles with nearly consistent activity and selectivity.

Synthesis of 2-Indolyl-1-nitroalkane Derivatives Using Nanocrystalline Titanium(IV) Oxide

Abstract The catalytic Friedel–Crafts alkylation of indoles with nitroalkenes to furnish 2-indolyl-1-nitroalkane derivatives at room temperature with moderate to excellent yields is reported using nanocrystalline titanium(IV) oxide (nano-TiO2) catalyst. In all cases, a single regioisomer was obtained. After completion of the reaction, the catalyst was recovered by centrifugation and activated under a nitrogen flow for 1 h at 250°C for further reuse. The nano-TiO2 can be reused for four cycles with a slight decrease of activity under the same reaction conditions.

Hydrogenation for Fine Chemical Synthesis: Status and Future Perspectives

Abstract This chapter presents an overview of hydrogenation processes carried out under ex situ and in situ conditions. It starts with a general description of fine chemicals and the importance of hydrogenation reactions for fine chemical synthesis. A discussion about asymmetric hydrogenation of organic compounds has also been presented. Various methods adopted for the synthesis of different catalysts and their applications for hydrogenation reactions has been discussed in detail.

Synthesis of fluorenones by using Pd(II)/Mg–La mixed oxide catalyst

Palladium(II)/magnesium–lanthanum mixed oxide (Pd(II)/Mg–La mixed oxide) catalyst was used in the dehydrogenative cyclization of benzophenones to afford fluorenones. This protocol represents a direct and facile approach to accessing a variety of fluorenone derivatives by means of C–H activation under heterogeneous conditions. The catalyst was recovered by centrifugation and used for three consecutive cycles with nearly consistent activity and selectivity.