TBAI/K₂S₂O₈ Initiated Radical Cyclization to Synthesize β‐ Arylsulfonyl Naphthalenes from Homopropargylic Alcohols and Sulfonyl Hydrazides

Abstract

A metal‐free radical addition method for the synthesis of β‐arylsulfonyl naphthalenes with homopropargylic alcohols and sulfonyl hydrazides has been developed. In this reaction, sulfonyl hydrazide is employed as the source of sulfonyl radical to produce the desired sulfone directly. There is the first example for homopropargylic alcohol through direct intramolecular addition of vinyl radical to arenes with sulfonyl radical, which is initiated by the TBAI/K2S2O8 reaction system and generates the desired products in moderate yields.magnified image

Sulfonyl Hydrazides in Organic Synthesis: A Review of Recent Studies

“…26‐2). The Yan group described a similar performance of homopropargylic alcohols in the consruction of β ‐arylsulfonyl naphthalenes. Direct intramolecular addition of vinyl radical to arenes and water elimination led to the final produts (Eq.…”

Electrochemically Induced Synthesis of Sulfonylated N-Unsubstituted Enamines from Vinyl Azides and Sulfonyl Hydrazides

“…On the basis of CV studies, control experiments, and literature data, ,− we propose the following pathway of enamine 3a electrosynthesis (Scheme ). The reaction begins from the anodic oxidation of the iodide anion to form molecular iodine, − which can further react with the iodide anion to result in I 3 – formation or with traces of water from the solvent, as well as hydroxide anions generated on the cathode to give electrophilic iodine species .…”

“…The reaction begins from the anodic oxidation of the iodide anion to form molecular iodine, − which can further react with the iodide anion to result in I 3 – formation or with traces of water from the solvent, as well as hydroxide anions generated on the cathode to give electrophilic iodine species . In the next step, p -toluenesulfonyl hydrazide 2a is oxidized with I 2 or I 3 – or electrophilic iodine-containing species [I] + forming S-centered sulfonyl radical B directly or through the formation of p -toluenesulfonyl iodide A . − Generated from A , via homolytic cleavage or probably, anodic oxidation, radical B is trapped with vinyl azide 1a resulting in a benzylic C-centered radical, which eliminates N 2 to form N-centered radical C . ,, Finally, abstraction of a hydrogen atom from 2a or THF by radical C leads to the formation of target product 3a via the imine D .…”

Oxidative Sulfonylation of Multiple Carbon‐Carbon bonds with Sulfonyl Hydrazides, Sulfinic Acids and their Salts

“…2‐Arylsulfonyl naphthalenes 386 were obtained through the reaction of homopropargyl alcohols 384 and sulfonyl hydrazides 385 with TBAI/K 2 S 2 O 8 and DMEDA in nitromethane at 90 °C (Scheme 170). [219] The cyclization process, as in the previous case, is initiated by the addition of sulfonyl radical A generated oxidatively from 385 to the triple bond of homopropargyl alcohol 384 to form vinyl radical B , which is intramolecularly cyclized into radical intermediate C . Subsequent hydrogen atom abstraction results in alcohol D , which eliminates water to give the final sulfonyl naphthalene 386 (Scheme 171).…”