Catalyst-free thiolation of indoles with sulfonyl hydrazides for the synthesis of 3-sulfenylindoles in water

Abstract

A water promoted thiolation of indoles with sulfonyl hydrazides has been developed under mild conditions in water.

Sulfonyl Hydrazides in Organic Synthesis: A Review of Recent Studies

“…Pathway A (Scheme ): electrophilic [RS + ] were used in the direct C−H functionalization of arenes. A heating condition was usually required during the thiolation of indoles, electron‐rich arenes (dimethoxylbenzenes, naphthalenes, phenols, dimethylbenzenes), and flavonoids . On the other hand, [RS + ] intermediate were successfully applied in the electrophilic addition to cyclic alkenyl iodides, which gave naphthylthioethers via a sequence of sulfenylation, deiodination, and aromatization.…”

Sulfenylation of C–H Bonds for C–S Bond Formation under Metal‐Free Conditions

“…Differently from previous reports, efficient thiolation of indoles with sulfonyl hydrazides in water in the absence of a catalyst was developed by Wang's group . Without any ligand or additive, a variety of 3‐sulfenylindoles were obtained with good to excellent yields.…”

Iodine‐Catalyzed One‐Pot Decarboxylative Sulfenylation of Electron‐Rich Arenes and Indoles

“…The electrophilic attack of PhS+ on 10 formed through the decarboxylation of 1 a , and generates another intermediate 13 with the elimination of 12 . Again the reaction of 12 with 2 a regenerates 8 to continue the reaction . Finally, oxidation of 13 with iodine in presence of oxygen give the desired product 3 a .…”