A copper-catalyzed cross-dehydrogenative coupling strategy has been developed for the synthesis of two classes of esters from simple solvents. The reaction of methylarenes with cyclic ethers resulted in α-acyloxy ethers involving four sp(3) C-H cleavages, while treatment of methylarenes with cycloalkanes led to the formation of allyl esters at the expense of six consecutive sp(3) C-H bonds.

A variety of styrenes and phenylacetylenes serve as excellent arylcarboxy sources in bringing about substrate directed o-benzoxylation of 2-phenylpyridine derivatives catalyzed by Cu(II) in the presence of TBHP. This reaction proceeds via formation of phenylglyoxal followed by decarbonylation to benzoyl radical/benzaldehyde which acts as the arylcarboxy source.

An efficient metal free protocol has been developed for the synthesis of benzylic esters via a cross dehydrogenative coupling (CDC) involving alkylbenzene(s) as a self- or as a cross-coupling partner(s) via the intermediacy of Ar-COOH and the benzylic carbocation obtained from the other half of the alkylbenzene; both symmetrical as well as unsymmetrical esters can be prepared using Bu4NI and TBHP.

An efficient Cu(I)-catalyzed synthesis of 3-aroylindoles has been achieved from o-alkynylated N,N-dimethylamines via a sp(3) C-H bond activation α to the nitrogen atom followed by an intramolecular nucleophilic attack with the alkyne using an aqueous solution of tert-butyl hydroperoxide (TBHP) as the oxidant. In this tandem catalytic synthesis of 3-aroylindoles both C-C and C-O bonds are installed at the expense of two sp(3) C-H bond cleavages.

A tandem and convergent approach to various N-, O-, or S-containing azoles has been developed by exploiting the thiophilic property of copper(I) iodide used in a catalytic quantity. The present protocol gives access to amino-substituted tetrazoles, triazoles, oxadiazoles and thiadiazoles via oxidative desulfurization of their respective precursors followed by inter-or intramolecular attack of suitable nucleophiles. For aminotetrazoles and triazoles an excellent regioselectivity has been achieved through proper tuning of the pK a values of the parent amines attached to unsymmetrical thioureas. The method represents an autocatalytic process in which copper(I) iodide gets converted to copper(II) sulfide which in turn transforms to active copper(II) oxide that effectively carries forward the catalytic cycle. The fate of the copper catalyst has also been studied using scanning electron microscopic (SEM) and energy-dispersive X-ray spectroscopic (EDS) analyses which give an insight into the mechanism for this catalytic process.