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We have successfully developed a transition metal free green methodology for the synthesis of carboxylic anhydrides from aldehydes via CDC pathway and have also demonstrated the reaction mechanism. The developed method has also been successfully applied for the synthesis of amides.

A one-pot simple and concise methodology has been developed for synthesizing aromatic carboxylic anhydrides starting from easily accessible aromatic aldehydes using cuprous chloride as the catalyst and TBHP as the oxidant in DMSO solvent to garner moderate to good yields via radical pathway in short and convenient reaction time at room temperature.

A novel and efficient methodology for the synthesis of 6H-benzo[c]chromenes, 6H-benzo[c]chromen-6-ones, carbazoles, dibenzofurans, dibenzooxepins has been developed. The reaction goes through intramolecular O-/N-arylations with sp2C–Br bonds via typical SNAr pathway in presence of potassium-tert-butoxide base.

The title compounds are efficiently obtained by intramolecular aryl C—H oxidative lactonization of 2-arylbenzaldehydes using tBuOOH as oxidant and CuCl as low-cost catalyst.

A short and convenient hetero-annulation protocol has been developed for the synthesis of substituted phenanthridines via domino Suzuki coupling and condensation between N -(2-iodo-aryl)-formamide derivatives and 2-formylphenylboronic acid in the presence of Pd(OAc) 2 , Cs 2 CO 3 and PPh 3 as catalytic system in dry DMF at 85–90 °C for 6–7 h. The intermediate after Suzuki coupling and deprotection of nitrogen under the same catalytic system, furnishes the corresponding phenanthridines in good yields after immediate condensation and dehydration.

The reaction yields decrease with an increasing electron-withdrawing effect of the substituents.

Phthalides have been synthesized exclusively in one pot via Pd-free Sonogashira coupling. A Cu-catalyzed domino Sonogashira coupling and 5-exo-dig cyclization between suitable substituted ortho-bromobenzoic acids and terminal alkynes afforded phthalides in good yields under mild reaction conditions.

An efficient method has been developed for the synthesis of bis-exocyclic conjugated diene containing 1,2,3,4-tetrahydroquinoline derivatives via palladium-catalyzed intramolecular Heck cyclization of (2-bromo-allyl)-(2-phenylethynyl-phenyl)-amines. The reaction followed 6-exo-dig cyclization to yield the desired products in moderate to good yields.

Two efficient hetero-annulation protocols have been developed for the synthesis of stable substituted c-fused thiophene derivatives with moderate to high yield. 3-(2-formyl-phenyl)-acrylic acid esters afforded benzo[c]thiophenes in the presence of phosphorus pentasulfide in refluxing benzene while 3-(2-formyl-cycloalkenyl)α,β-unsaturated esters resulted in the formation of c-fused thiophene derivatives when reacted with sodium sulfide in refluxing tetrahydrofuran.

A facile, mild, efficient, and copper-free method has been developed for the synthesis of 2-substituted indoles via domino Sonogashira coupling/cyclization reaction catalyzed by ZnCl2 and palladium on carbon with simultaneous formations of C–C and C–N bonds.

A convenient and short methodology has been developed towards the synthesis of highly substituted phenanthridines and their analogous benzo[k] and benzo[i] derivatives in a single step via Suzuki coupling and condensation between suitably substituted aromatic ortho-bromoaldehydes and ortho-aminobenzeneboronic acids in good to excellent yields.

The synthesis of the title compounds is achieved from aryl bromides and 2-aminophenylboronic acid under mild reaction conditions.