Dioxygen-Triggered Oxidative Radical Reaction: Direct Aerobic Difunctionalization of Terminal Alkynes toward β-Keto Sulfones

Lu, Qingquan; Zhang, Jian; Zhao, Ganglu; Qi, Yue; Wang, Huamin; Lei, Aiwen

doi:10.1021/ja4052685

Cited by 460 publications

(176 citation statements)

References 68 publications

(26 reference statements)

Supporting

Mentioning

168

Contrasting

Unclassified

Order By: Relevance

“…Then, alkynes were utilized instead of alkenes under similar reaction conditions. 61 A variety of β-keto sulfones were obtained (Scheme 30). The vinyl peroxide intermediate was generated, which undergoes subsequent reduction and isomerization to furnish the final product.…”

Section: Model III In Radical Oxidativementioning

confidence: 99%

Recent Advances of Transition-Metal Catalyzed Radical Oxidative Cross-Couplings

2014

Self Cite

View full text Add to dashboard Cite

CONSPECTUS: Oxidative cross-coupling reactions between two nucleophiles are a powerful synthetic strategy to synthesize various kinds of functional molecules. Along with the development of transition-metal-catalyzed oxidative cross-coupling reactions, chemists are applying more and more first-row transition metal salts (Fe, Co, etc.) as catalysts. Since first-row transition metals often can go through multiple chemical valence changes, those oxidative cross-couplings can involve single electron transfer processes. In the meantime, chemists have developed diverse mechanistic hypotheses of these types of reactions. However, none of these hypotheses have led to conclusive reaction pathways until now. From studying both our own work and that of others in this field, we believe that radical oxidative cross-coupling reactions can be classified into four models based on the final bond formations. In this Account, we categorize and summarize these models. In model I, one of the starting nucleophiles initially loses one electron to generate its corresponding radical under oxidative conditions. Then, bond formations between this radical and another nucleophile create a new radical, [Nu(1)-Nu(2)](•), followed by a further radical oxidation step to generate the cross-coupling product. The radical oxidative alkenylation with olefin, radical oxidative arylative-annulation, and radical oxidative amidation are examples of this model. In model II, one of the starting nucleophiles loses its two electrons via two steps of single-electron-transfer to generate an electrophilic intermediate, followed by a direct bond formation with the other nucleophile. For example, the oxidative C-O coupling of benzylic sp(3) C-H bonds with carboxylic acids and oxidative C-N coupling of aldehydes with amides are members of this model group. For model III, both nucleophiles are oxidized to their corresponding radicals. Then, the radicals combine to form the final coupling product. The dioxygen-involved radical oxidative cross-couplings between sulfinic acids and olefins or alkynes belong to this bond formation model. Lastly, in model IV, one nucleophile loses two electrons to generate an electrophilic intermediate, while the other nucleophile loses one electron to generate a radical. Then, a bond forms between the cation and the radical to generate a cationic radical, followed by a one-electron reduction to afford the final coupling product. The oxidative coupling between arylboronic acids and simple ethers was classified in this model. At the current stage, there are only a few examples presented for models III and IV, but they represent two types of potentially important transformations. More and more examples of these two models will be developed in the future.

show abstract

Section: Model III In Radical Oxidativementioning

confidence: 99%

Recent Advances of Transition-Metal Catalyzed Radical Oxidative Cross-Couplings

2014

Self Cite

View full text Add to dashboard Cite

show abstract

“…3 Commonly, β-ketosulfones are prepared by the alkylation of sodium sulfinates with α-halo-ketones or α-tosyloxy ketones, which suffer from some limitations such as the pre-functionalized materials, relatively complicated or harsh reaction conditions and undesired byproducts. 4 For recent years, much effort has been devoted to expanding radical sulfonylation of carbon−carbon multiple bonds for constructing β-keto-sulfones and these methods have been well developed by the group of Lipshutz, 5 Yadav, 6 Wang, 7 Huang, 8 Lei, 9 and Loh. 10 However, despite some progress has been made, the problem of the potential metal contamination are still involved in most of these transformations, which will limit their massive applications in the pharmaceutical industry.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of β-keto-sulfones via metal-free TBAI/TBHP mediated oxidative cross-coupling of vinyl acetates with sulfonylhydrazides

Tang

Fan

Gao

et al. 2015

Tetrahedron Letters

View full text Add to dashboard Cite

“…Recently Co/Mn-mediated 16 and also Cu/TEMPO-mediated 17 sulfones with high selectivity. 19 Kim et al have used a NaOtBu-O 2 system for the formation of carboxylic acids from vic-1,2-diols. 20 To the best of our knowledge, this aerobic system was not studied for the oxidation of indolyl compounds.…”

Section: Introductionmentioning

confidence: 99%

Transition-metal free highly selective aerobic oxidation of hindered 2-alkylindoles

et al. 2015

View full text Add to dashboard Cite

a b s t r a c tA novel and easy access to highly complex 3-oxoindolin-2-ylidene derivatives from the exposure of Ugiadducts bearing an indolyl moiety in Cs 2 CO 3 /DMF to air is reported. This is the first example of aerobic oxidation of 2-alkylindoles to 3-oxoindolin-2-ylidenes. Some advantages of this method are the use of air as oxygen source, transition metal-free reagents and simple conditions, a multicomponent and one-pot process and highly regio-and stereoselective manner to trans-3-oxoindolin-2-ylidenes.

show abstract

Dioxygen-Triggered Oxidative Radical Reaction: Direct Aerobic Difunctionalization of Terminal Alkynes toward β-Keto Sulfones

Cited by 460 publications

References 68 publications

Recent Advances of Transition-Metal Catalyzed Radical Oxidative Cross-Couplings

Recent Advances of Transition-Metal Catalyzed Radical Oxidative Cross-Couplings

Synthesis of β-keto-sulfones via metal-free TBAI/TBHP mediated oxidative cross-coupling of vinyl acetates with sulfonylhydrazides

Transition-metal free highly selective aerobic oxidation of hindered 2-alkylindoles

Contact Info

Product

Resources

About