M. Madhava Reddy

Cobalt catalyzed oxidation of cyclic alkenes with molecular oxygen: allylic oxidation versus double bond attack

Cobalt(II) Schiffs base complex 1 and 2 exhibit a remarkable chemoselectivity during oxidation of cyclic alkenes with molecular oxygen in the presence of 2- methylpropanal. Catalyst 1 encourages the oxidation of double bond to give epoxide as the major product whereas catalyst 2 promotes mainly the allylic oxidation leading to allylic alcohols or enones.

A versatile cobalt(II)-Schiff base catalyzed oxidation of organic substrates with dioxygen: Scope and mechanism

Abstract Cobalt(II) complex 1a-f derived from Schiff bases act as efficient catalysts during the oxidation of wide range of organic substrates(e.g. alkenes, alcohols, benzylic compounds and aliphatic hydrocarbons) with dioxygen in the presence of aliphatic aldehydes or ketones or ketoesters. EPR studies on 1a-f complexes suggest that the aliphatic carbonyl compounds promote the formation of a cobalt(III)-superoxo species responsible for the oxidation of organic compounds. These studies also demonstrate the role of ligands on cobalt in controlling the chemoselectivity of these oxidations. A plausible mechanistic rational is also provided for these oxidations.

Cobalt-catalysed three-component coupling involving ketones or ketoesters, aldehydes and acetonitrile: a novel one-pot synthesis of β-acetamido ketones

Cobalt(II) chloride catalyses one-pot coupling of ketones or ketoesters, aldehydes and acetonitrile in the presence of acetyl chloride to give β-acetamido ketones 3 in good yields.

Cobalt (II) catalysed allylation of 1,3-dicarbonyl compounds with allyl acetates

An efficient allylation of various 1,3-dicarbonyl compounds can be achived with allyl acetates in the presence of catalytic cobalt (II) chloride in 1,2-dichloroethane.

A one pot synthesis of β-acetamido ketones and furans by cobalt(II) catalyzed coupling of 1,3- or 1,4- dicarbonyl compounds and aldehydes: a remarkable role of dioxygen

Cobalt(II) catalyses the coupling of 1,3- and 1,4-dicarbonyl compounds with various aldehydes in the presence of acetonitrile to give β-acetamido ketones and furan amides respectively. The outcome of these reactions is controlled by the reaction atmosphere as aromatic aldehydes react to give β-ketoamide in the presence of nitrogen, whereas the reaction with aliphatic aldehydes gives the later product only in the presence of oxygen atmosphere.

Cobalt(II) chloride catalysed conversion of allylic alcohols to rearranged allylic amides

Secondary and tertiary allylic alcohols can be converted to the corresponding allylically rearranged amides and acetates in presence of a catalytic quantity of cobalt(II) chloride and acetic anhydride in acetonitrile. Tertiary alcohols undergo complete rearrangement whereas the secondary ones yield a mixture of regioisomers.

Cobalt catalyzed regioselective allylation of 1,3-dicarbonyl compounds

Catalytic amount of Cobalt(II) chloride in 1,2-dichloroethane promotes the allylation of 1,3-dicarbonyl compounds with allyl acetates in high yields. The allylation of pentane-2,4-dione is highly regioselective as compared with methylacetoacetate and ethyl 2-oxocyclopentanecarboxylate.

A one pot cobalt catalyzed regio- and stereoselective synthesis of oxazolidin-2-thiones from alkenes and trimethylsilylisothiocyanate

Efficient synthesis of Oxazolidin-2-thiones can be achieved from alkenes by employing a one pot Cobalt complex 1 catalyzed aerobic epoxidation followed by its cleavage with trimethylsilylisothiocyanate.

Cobalt(II) Complex Catalysed Epoxidation with Molecular Oxygen

Abstract Cobalt(II) complexes 1 or 2, catalyses the epoxidation of alkenes in the presence of molecular oxygen and 2-methylpropanal in high yields.