G. Santosh Kumar

A copper-catalyzed multi-component reaction accessing fused imidazo-heterocycles via C–H functionalization

An efficient synthesis of fused imidazo-heterocycles is described using Cu(OTf)2 in [bmim]BF4 by the multi-component reaction of pyridin-2(1H)-one or thiazol/benzo[d]thiazol-2(3H)-ones with O-tosylhydroxyl amine and acetophenones under microwave irradiation. The present method is very rapid and the product formation occurs via a C–H functionalization/tandem addition-cyclization process. The ionic liquid containing copper triflate is recovered and reused four times.

DABCO-Promoted Efficient and Convenient Synthesis of Benzofurans

Abstract An efficient and convenient synthesis of benzofurans has been described from phenacyl halides and o-hydroxy benzaldehyde in the presence of DABCO. The procedure is applicable for a variety of phenacyl halides and provide a variety of benzofurans. DABCO act as a base and as well as nucleophile. GRAPHICAL ABSTRACT

Boric Acid–Mediated Mild and Efficient Friedel–Crafts Alkylation of Indoles with Nitro Styrenes

An efficient method has been developed for the synthesis of indole 3-derivatives by the Friedel–Crafts alkylation of indole with nitro olefins in presence of boric acid in aqueous medium.

Indium/Fe(III) – mediated regioselective β-cross-coupling aldol type addition reaction of activated alkenes with isatins/isatinimines in aqueous media

A highly efficient and regioselective β-cross coupling aldol type addition reaction of activated alkenes with isatin/isatinimine derivatives in the presence of Indium/Fe(III) in THF/H2O at room temperature is described. Our synthetic protocol explores a broad substrate scope and smoothly proceeds under base-free conditions. The resulting products are obtained in a short reaction time with moderate to high yields. This is the first example of Mannich-type coupling of isatinimines with activated alkenes to afford the alkyl 3-(2-oxo-3-(phenylamino)indolin-3-yl)propanoates and 3-(3-oxoalkyl)-3-(phenylamino)indolin-2-ones.

A Ru(III) – catalyzed α-cross-coupling aldol type addition reaction of activated olefins with isatins

A α-cross-coupling aldol type addition reaction activated olefins with isatins has been described in the presence of ruthenium(III) chloride and tributyltin hydride (TBTH) at room temperature. This method is found to work consistently for the delivering of ene-carbonyl coupled products in good to excellent yields with moderate to acceptable selectivity. The substrate scope of the present method was briefly discussed.