A metal-free I/TBHP induced highly atom economic and operationally simple oxidative cross-coupling reaction has been developed for the direct synthesis of sulfenamides/sulfanes/disulfides from the reaction of 4-hydroxydithiocoumarin and amines/thiols. The novelties of the present protocol are unprecedented S-C bond formation in addition to S-N and S-S bonds, shorter reaction time, mild and environmentally benign reaction conditions, functional group tolerance and moderate to excellent yields. Moreover, the four newly synthesized compounds namely 4q, 6d, 6e and 7a exhibit anti-proliferative activity against the breast cancer cell line MCF7, and may be lead molecules for future drug development.

Direct electrochemical oxidative functionalization of caffeine under metal‐free and external‐oxidant‐free conditions was achieved. Nucleophiles such as various substituted pyrazoles, alcohols, and sodium trifluoromethanesulfonate can be utilized with high diastereoselectivity for the dearomatizative functionalization of caffeine. In addition, selective C2 functionalization of caffeine has also been realized with the modification of solvent and reaction time. A gram‐scale experiment demonstrates the potential application in the derivatization of caffeine.

Synthesis of 3-sulfenyl indole derivatives is achieved through oxidative cross-dehydrogenative coupling reaction. A few such newly synthesized compounds have also exhibited anti-proliferative activity via reactive oxygen species mediated cell damage.

A convenient and highly efficient synthetic protocol is reported for the synthesis of hitherto unreported thiopyrano{2,3b:6,5-b′}bis(thiochromene)-12,14(13H)-diones by a domino pseudo-three-component reaction utilizing 4-hydroxydithiocoumarin and aldehydes. Single-crystal X-ray crystallographic analysis of the 13-phenyl-12H-thiopyrano[2,3-b:6,5-b′]bis(thiochromene)-12,14(13H)dione derivative shows a layered structure that is stabilized by the unexpected C-S•••π interactions.

A simple and an efficient method for the regioselective synthesis of N-alkyl/aryl/H 3-arylindole derivatives from N-substituted anilines and trans-β-nitrostyrenes has been described using 10 mol% of bismuth(iii) triflate as a catalyst in acetonitrile at 80 °C. The present protocol profits from the formation of new C-C and C-N bonds, broad substrate scope and moderate to good yields.

An efficient and facile regioselective synthesis of di- and tri-substituted 3,4-dihydrothiochromeno[3,2-e][1,3]thiazin-5(2H)-one derivatives was achieved through an ytterbium triflate catalysed pseudo four component hetero-Diels–Alder reaction.

An unprecedented and efficient method for the synthesis of useful thieno[2,3-b]thiochromen-4-one oximes is accomplished via a thio[3 + 2] cyclization reaction of 4-hydroxydithiocoumarins and trans-β-nitrostyrenes in the presence of 10 mol% KCO in ethanol under reflux conditions. Furthermore, hitherto, these precursors were converted into the corresponding 2-amino thieno[2,3-b]thiochromen-4-one and 2-nitroso thieno[2,3-b]thiochromen-4-one derivatives respectively. The salient features of the present protocol are mild reaction conditions, shorter reaction times, good yields and unexpected formation of C-C and C-S bonds in a regioselective manner.

Yb(OTf) 3 Catalyzed Regioselective Synthesis of Unusual Di-and Tri-Substituted 3,4-Dihydrothiochromeno[3,2-e][1,3]thiazin-5(2H)-one Derivatives Through a Pseudo Four-Component Hetero-Diels-AlderReaction. -(MAHATO, K.; BAGDI, P. R.; KHAN*, A. T.; RSC Adv. 5 (2015) 59, 48104-48111, http://dx.