Arumugam Sudalai

WO3-30% H2O2-cinchona alkaloids: a new heterogeneous catalytic system for the asymmetric oxidation of sulfides and the kinetic resolution of racemic sulfoxides

Abstract WO 3 -catalyzed asymmetric oxidation of thioethers and kinetic resolution of sulfoxides with 30% aq. H 2 O 2 in the presence of cinchona alkaloids under heterogeneous conditions affords chiral sulfoxides in high yields with moderate to good enantioselectivities.

N-Bromoamides as versatile catalysts for aziridination of olefins using chloramine-T

N-Bromoamides catalyze effectively the aziridination of electron-deficient as well as electron-rich olefins using chloramine-T (N-chloro-N-sodio-p-toluenesulfonamide) as a nitrogen source under ambient conditions to afford the corresponding aziridines in good to excellent yields.

N-Heterocyclic carbene catalyzed regioselective oxo-acyloxylation of alkenes with aromatic aldehydes: a high yield synthesis of α-acyloxy ketones and esters

An N-heterocyclic carbene (NHC)-catalyzed reaction of alkenes with aromatic aldehydes providing for a high yield synthesis of α-acyloxy ketones and esters has been described. This unprecedented regioselective oxidative process employs NBS and Et3N in stoichiometric amounts and O2 (1 atm) as an oxidant under ambient conditions in DMSO as a solvent.

Pd-Catalysed Regiospecific Reductive Ring Opening of Epoxides and Glycidic Esters

Abstract The regiospecific ring opening of epoxides was achieved by Pd-catalysed transfer hydrogenolysis using ammonium formate as hydrogen source.

Organocatalytic [4+1]-annulation approach for the synthesis of densely functionalized pyrazolidine carboxylates

A novel one-pot [4+1]-annulation process for the asymmetric synthesis of densely functionalized pyrazolidine carboxylates is described. The in situ generated γ-hydrazino-α,β-unsaturated ester obtained via proline catalysis acts as a four-atom component, and Coreys sulfur ylide or ethyl bromoacetate acts as a one-atom carbon source to construct pyrazolidine carboxylate units in a highly enantio- and diastereoselective fashion.

Concise Enantioselective Synthesis of Naturally Active (S)-3-Hydroxypiperidine

Abstract A short and efficient enantioselective synthesis of natural product (S)-3-hydroxypiperidine has been achieved starting from commercially available raw materials employing two catalytic routes: (i) cocatalyzed hydrolytic kinetic resolution (HKR) of racemic methyl-3-(oxiran-2-yl)propanoate; (ii) proline-catalyzed α-aminooxylation followed by Horner–Wardsworth–Emmons olefination in high enantiomeric purity (97% ee) and high overall yield (38%). GRAPHICAL ABSTRACT

Ni-Catalyzed Dimerization and Hydroperfluoroarylation of 1,3-Dienes

A nickel-catalyzed three-component coupling reaction between perfluoroarenes and two molecules of a 1,3-diene in the presence of an alkyl Grignard reagent, which acted as a hydride source, provided 3-perfluoroarylated-1,7-octadienes via 1,3-diene dimerization and subsequent perfluoroarylation upon C-F bond cleavage. The reaction proceeded smoothly in a regioselective manner by simply combining NiCl2 and PPh3 as a catalyst and tolerated various functional groups on the perfluoroarenes. When substituted perfluoroarenes were employed, the reaction selectively occurred at the para-position. Mechanistic studies revealed that an anionic Ni complex, generated upon the reaction of Ni(0) with two molecules of a 1,3-diene and an alkyl Grignard reagent, played an important role in the C-C bond forming step with perfluoroarenes. The C-F bond cleavage was found to be a relatively fast step in the catalytic cycle.