Oxidative Cleavage of Csp3-Csp2 and Csp3-H Bonds with KOtBu: Highly Robust and Practical Synthesis of Diaryl/(het-Ar) Ketones.

Herein, we report an efficient and practical approach for synthesizing diaryl(het) ketones from R-CO-CHR-Ar through a simultaneous oxidative cleavage of C-C and C-H bonds using KOtBu. This method enables synthesizing a variety of unsymmetrical and symmetrical (hetero)aryl ketones in excellent yields, which are otherwise difficult to make. Besides, we synthesized natural products using this method.

Visible-Light-Mediated Difunctionalization of Alkynes: Synthesis of ß-Substituted Vinylsulfones Using O- and S-Centered Nucleophiles.

An inimitable illustration of a green-light-induced, regioselective difunctionalization of terminal alkynes has been disclosed using sodium arylsulfinates and carboxylic acids in the presence of eosin Y as the photocatalyst. The present methodology is further demonstrated by employing NH4SCN as an S-centered nucleophile instead of carboxylic acid. The mechanistic investigation reveals a radical-induced iodosulfonylation followed by a base-mediated nucleophilic substitution. The mechanism is supported by various studies, viz., radical-trapping experiment, fluorescence quenching, and CV studies. In this protocol, (Z)-ß-substituted vinylsulfones are obtained, exclusively covering a broad range of alkynes and nucleophiles, which are often unaddressed. The present strategy can tolerate structurally discrete substrates with steric bulk and different electronic properties, which provides a straightforward and practical pathway for the synthesis of highly functionalized (Z)-ß-substituted vinylsulfones. Herein, C-O and C-S bonds are assembled simultaneously with the concomitant introduction of important functional groups, viz., ester, thiocyanate, and sulfone.

Cyano-Sacrificial (Arylthio)arylamination of Quinoline and Isoquinoline N-Oxides Using N-(2-(Arylthio)aryl)cyanamides.

A copper(I)-catalyzed regioselective arylthio-arylamination of quinoline and isoquinoline N-oxides has been achieved at the expense of a cyano (CN) group from N-(2-(arylthio)aryl)cyanamides. This reductive amination proceeds in one pot at 80 °C in the absence of any additives. This is a unique demonstration of aryl cyanamides serving as arylaminating agents on quinoline/isoquinoline N-oxides with concurrent autoreduction of N-oxide.

Three Sequential C-N Bond Formations: tert-Butyl Nitrite as a N1 Synthon in a Three Component Reaction Leading to Imidazo[1,2-a]quinolines and Imidazo[2,1-a]isoquinolines.

tert-Butyl nitrite serves the dual role of an oxidant as well as a N1 synthon in a multicomponent reaction involving quinolines, isoquinolines, and styrenes. Herein, two sp2 C-H functionalizations of styrenes and one sp2 C-H functionalization of quinolines and isoquinolines lead to the formation of fused quinolines and isoquinolines via three sequential C-N bond formations.

Cs2CO3 as a source of carbonyl and ethereal oxygen in a Cu-catalysed cascade synthesis of benzofuran [3,2-c] quinolin-6[5-H]ones.

The simultaneous construction of C-C, C-O, and C-N bonds utilizing Cs2CO3 as a source of both carbonyl (CO) and ethereal oxygen and a cascade synthesis of benzofuro[3,2-c]quinolin-6(5H)-one have been achieved using a combination of Cu(OAc)2 and Ag2CO3. A plausible mechanism has been proposed for this unprecedented transformation.

Regiospecific Benzoylation of Electron-Deficient N-Heterocycles with Methylbenzenes via a Minisci-Type Reaction.

A regioselective cross-dehydrogenative coupling between electron-deficient N-heterocycles (isoquinoline, quinolines, and quinoxalines) and methylbenzenes leading to regiospecific C-aroylation has been accomplished using AlCl3 as the catalyst in the presence of oxidant TBHP. This protocol is a practical alternative to the classical Minisci reaction.

Cyclic ethers to esters and monoesters to bis-esters with unconventional coupling partners under metal free conditions via sp(3) C-H functionalisation.

An efficient metal free oxidative esterification of sp(3) C-H bonds (adjacent to an oxygen atom) in simple solvents like 1,4-dioxane, tetrahydropyran, tetrahydrofuran and ethyl acetate has been achieved using terminal aryl alkenes and alkynes as the ArCOO(-) sources.