Copper‐Catalyzed Extended Pummerer Reactions of Ketene Dithioacetal Monoxides with Alkynyl Sulfides and Ynamides with an Accompanying Oxygen Rearrangement

Abstract

The first examples of metal-catalyzed extended Pummerer reactions through the activation of sulfoxides are described. The copper-catalyzed reactions of ketene dithioacetal monoxides with alkynyl sulfides and ynamides provided a wide variety of γ,γ-disulfanyl-β,γ-unsaturated carbonyl compounds with an accompanying oxygen rearrangement. The products can be easily converted into 1,4-dicarbonyl compounds and substituted heteroaromatics. DFT calculations and mechanistic experiments revealed a new interesting stepwise addition/oxygen rearrangement mechanism.

Gold‐Catalyzed, Iodine(III)‐Mediated Direct Acyloxylation of the Unactivated C(sp3)–H Bonds of Methyl Sulfides

“…On the basis of the above experimental results and previous research from other groups,, a plausible reaction mechanism is proposed and is shown in Scheme ; it has some variations to the Pummerer rearrangement. [17d] We presume that the hypervalent iodine compound acts as a Lewis acid, similar to the activation of sulfoxides with strong acids .…”

Bond-Forming and -Breaking Reactions at Sulfur(IV): Sulfoxides, Sulfonium Salts, Sulfur Ylides, and Sulfinate Salts

“…In 2013, the same group reported this reaction with thioalkynes and ynamides as nucleophiles (Scheme 24). 71 Interestingly, copper bromide was used as the activating agent to enhance the electrophilicity of the vinyl sulfoxide toward nucleophilic attack. An intramolecular sulfur-to-carbon oxygen transfer was proposed to lead to copper enolate 118 , which affords the ketene dithioacetals 119 after proton transfer.…”

C−H Coupling Reactions Directed by Sulfoxides: Teaching an Old Functional Group New Tricks

“…Matsubara, Yorimitsu, and Oshima showed that ketene dithioacetal monoxides 85 can also be coupled with alkynyl sulfides or ynamides under copper catalysis (Scheme 34). [52] Scheme 31. Procter's sulfoxide-directed CÀH/CÀHcoupling of arenes and alkynes.…”

“…Matsubara, Yorimitsu, and Oshima showed that ketene dithioacetal monoxides 85 can also be coupled with alkynyl sulfides or ynamides under copper catalysis (Scheme ) . In this case, the copper catalyst activates the sulfoxide for a Pummerer‐type reaction whereby the electron‐rich alkyne reacts with the vinyl position of the activated sulfoxide 86 .…”