A silver- and copper-free rhodium-catalyzed C-H acetoxylation reaction of azaindoles has been achieved at near ambient temperature employing PIDA as a nonmetallic acetoxy source. The method is highly selective, efficient, and scalable and requires acetic anhydride as the sole additive. The scope of the reaction has been successfully tested with a wide array of medicinally important heterocyclic scaffolds with diverse functional group tolerance. A series of kinetic experiments was conducted to gain detailed insight into the reaction mechanism. The methodology developed could be successfully expanded for C7-acetoxylation of indoline derivatives using pyrimidine as a detachable directing group for the synthesis of 7-hydroxyindole.

An efficient, highly regioselective, and scalable ruthenium-catalyzed o-aryl C-H mono-cyanation of N-aryl-7-azaindoles to form N-(2-cyanoaryl)-7-azaindoles has been developed through N-directed ortho C-H activation using N-cyano-N-phenyl-p-toluenesulfonamide as cyanating reagent in the presence of AgOTf and NaOAc in DCE. A range of substrates has furnished cyanated azaindoles in good to excellent yields under the simple reaction conditions. Involvement of C-H metalation has been supported by a kinetic study. This methodology provides easy access to a class of pharmaceutically significant molecules and their precursors.

A copper(I)-promoted cycloalkylation-peroxidation strategy has been developed via a three-component reaction involving cycloalkanes, tert-butyl hydroperoxide (TBHP) and internal conjugated alkenes possessing electron-withdrawing groups (EWGs). This process installs C-O and C-C bonds via sp(3) C-H functionalisation with concomitant generation of two stereocentres. This regioselective radical addition of coumarin system is opposite to that of styrene.

An Ir(III)-catalyzed [3 + 2] annulation of weakly coordinating N-sulfonyl ketimines with challenging α, βunsaturated nitro olefins has been achieved via redox-neutral C−H functionalization in the presence of a catalytic amount of silver hexafluoroantimonate. The generation of three consecutive stereogenic centers in a single step via direct C−H functionalization is the prime feature of this methodology. A wide array of pharmaceutically relevant nitro-substituted spirocyclic benzosultams was synthesized with good to excellent diastereoselectivity as well as in high yield starting from easily accessible substrates.

Rhodium catalyzed synthesis of chalcogenated N-aryl-7-azaindoles/azaindolines has been developed through N-directed ortho Csp 2 ÀH activation in presence of silver triflate and silver carbonate in 1,4-dioxane using dichalcogenides. We have established this methodology as being efficient, highly regioselective and scalable, having a broad substrates scope. Through this route, a range of substrates have furnished thiolation and selenylation of azaindoles and azaindolines in good to excellent yields. These molecules could have potential application in biological and/or material science.

A straightforward strategy for direct incorporation of sulfonyl units into xanthene moiety for accessing xanthen-9-sulfone derivatives in good to excellent yields has been established via metal-free radical-radical cross-coupling reaction of...

Imino-/enaminophosphonates derived from aminesand diethylphenacylphosphonates undergo oxidative cyclization via C À Hb ond activation catalyzed by palladium chloride to provide ac onvenient route for the synthesis of substituted indol-3-yl and pyrrol-3-yl phosphonates.

Ir(III)-catalyzed unprecedented mild C-H amidation for weakly coordinating cyclic N-sulfonyl ketimines, accelerated by a mono protected l-amino acid, has been developed. The method uses 1,4,2-dioxazol-5-ones as the robust amidating reagent in conjunction with a catalytic amount of silver triflate. It is highly selective and does not require a stoichiometric amount of oxidants or additives. A series of mechanistic experiments was performed to gain some insights into the reaction mechanism. The strategy provides easy access to novel benzosultam-quinazoline and benzosultam-quinazolinone hybrid scaffolds endowed with pharmaceutically relevant features.