Metal‐Free I₂‐Catalyzed Sulfenylation of Dihydropyrans: Synthesis of Vinyl Sulfides

Abstract

I2‐catalyzed C(sp2)–H bond sulfenylation have been achieved from the reaction of thiols or disulfides with dihydropyrans under metal‐free conditions. This catalytic system was also used for thiol‐free achievement of sulfenylated dihydropyrans from aryl halides in the presence of CuI and potassium isopropyl xanthate as an effective source of sulfur.

Transition Metal‐Free Sulfenylation of C−H Bonds for C−S Bond Formation in Recent Years: Mechanistic Approach and Promising Future

“…Safari and co‐workers [248] have reported metal‐free, iodine‐mediated sulfenylation of dihydropyrans ( 400 ) using thiophenol ( 9 ) as sulfenylating agent to synthesize vinyl sulfides ( 401 ). The substrate scope was investigated by employing electronically diverse thiophenols and resulted into desired product in good yield.…”

“…I 2 /DMSO mediated synthesis of sulfenyliodide ( 401 A ) from thiophenol was proposed in the mechanism, followed by its reaction with dihydropyrans that resulted into desired product (Scheme 134). [248] …”

“…Yang and co-workers [229] explored the catalytic potential of iodine in mediating three-component sulfenylation of alkene. The optimized reaction condition was successfully applied to the synthesis of β-alkoxy sulfides (350) by reacting alkenes (248) with sulfonyl hydrazides (258) in presence alcohols (349). The methodology tolerated well alkenes as well as sulfenyl hydrazides substituted with both electron donating and withdrawing groups (Scheme 113).…”

“…Nucleophilic attack of electron rich aryl conjugates on sulfenyliodide followed by the removal of proton leads to formation of desired product (396). [247] Safari and co-workers [248] have reported metal-free, iodinemediated sulfenylation of dihydropyrans (400) using thiophenol (9) as sulfenylating agent to synthesize vinyl sulfides (401). The substrate scope was investigated by employing electronically diverse thiophenols and resulted into desired product in good yield.…”

“…I 2 /DMSO mediated synthesis of sulfenyliodide (401 A) from thiophenol was proposed in the mechanism, followed by its reaction with dihydropyrans that resulted into desired product (Scheme 134). [248] Bodhak and co-workers [249] have reported an iodine catalyzed, transition metal-free, multicomponent reaction of phenacyl bromide (402), thioureas (403) and arylthiols/ heteroaryl thiols (9). The standardized reaction conditions were applied successfully to synthesize 5-sulfenyl-2-iminothiazolines (404, 405).…”