Ketyl Radical Reactivity Via Atom Transfer Catalysis

Overview

Journal Science

Specialty Science

Date 2018 Oct 13

PMID 30309953

Citations 33

Authors

Lu Wang

Jeremy M Lear

Sean M Rafferty

Stacy C Fosu

David A Nagib

Affiliations

Soon will be listed here.

Abstract

Single-electron reduction of a carbonyl to a ketyl enables access to a polarity-reversed platform of reactivity for this cornerstone functional group. However, the synthetic utility of the ketyl radical is hindered by the strong reductants necessary for its generation, which also limit its reactivity to net reductive mechanisms. We report a strategy for net redox-neutral generation and reaction of ketyl radicals. The in situ conversion of aldehydes to α-acetoxy iodides lowers their reduction potential by more than 1 volt, allowing for milder access to the corresponding ketyl radicals and an oxidative termination event. Upon subjecting these iodides to a dimanganese decacarbonyl precatalyst and visible light irradiation, an atom transfer radical addition (ATRA) mechanism affords a broad scope of vinyl iodide products with high -selectivity.

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References

Szostak M, Fazakerley N, Parmar D, Procter D . Cross-coupling reactions using samarium(II) iodide. Chem Rev. 2014; 114(11):5959-6039. DOI: 10.1021/cr400685r. View

Ischay M, Anzovino M, Du J, Yoon T . Efficient visible light photocatalysis of [2+2] enone cycloadditions. J Am Chem Soc. 2008; 130(39):12886-7. DOI: 10.1021/ja805387f. View

Koh M, Nguyen T, Zhang H, Schrock R, Hoveyda A . Direct synthesis of Z-alkenyl halides through catalytic cross-metathesis. Nature. 2016; 531(7595):459-65. PMC: 4858352. DOI: 10.1038/nature17396. View

Nguyen K, Park B, Luong T, Sato H, Garza V, Krische M . Metal-catalyzed reductive coupling of olefin-derived nucleophiles: Reinventing carbonyl addition. Science. 2016; 354(6310). PMC: 5130112. DOI: 10.1126/science.aah5133. View

Monks B, Cook S . Palladium-catalyzed intramolecular iodine-transfer reactions in the presence of β-hydrogen atoms. Angew Chem Int Ed Engl. 2013; 52(52):14214-8. DOI: 10.1002/anie.201308534. View

Wallentin C, Nguyen J, Finkbeiner P, Stephenson C . Visible light-mediated atom transfer radical addition via oxidative and reductive quenching of photocatalysts. J Am Chem Soc. 2012; 134(21):8875-84. DOI: 10.1021/ja300798k. View

Montgomery J . Nickel-catalyzed reductive cyclizations and couplings. Angew Chem Int Ed Engl. 2004; 43(30):3890-908. DOI: 10.1002/anie.200300634. View

Andrieux C, Pinson J . The standard redox potential of the phenyl radical/anion couple. J Am Chem Soc. 2003; 125(48):14801-6. DOI: 10.1021/ja0374574. View

Theriot J, Lim C, Yang H, Ryan M, Musgrave C, Miyake G . Organocatalyzed atom transfer radical polymerization driven by visible light. Science. 2016; 352(6289):1082-6. DOI: 10.1126/science.aaf3935. View

10.

Nguyen J, DAmato E, Narayanam J, Stephenson C . Engaging unactivated alkyl, alkenyl and aryl iodides in visible-light-mediated free radical reactions. Nat Chem. 2012; 4(10):854-9. DOI: 10.1038/nchem.1452. View

11.

Kischkewitz M, Okamoto K, Muck-Lichtenfeld C, Studer A . Radical-polar crossover reactions of vinylboron ate complexes. Science. 2017; 355(6328):936-938. DOI: 10.1126/science.aal3803. View

12.

Tasker S, Standley E, Jamison T . Recent advances in homogeneous nickel catalysis. Nature. 2014; 509(7500):299-309. PMC: 4344729. DOI: 10.1038/nature13274. View

13.

Ye C, Melcamu Y, Li H, Cheng J, Zhang T, Ruan Y . Dual catalysis for enantioselective convergent synthesis of enantiopure vicinal amino alcohols. Nat Commun. 2018; 9(1):410. PMC: 5789022. DOI: 10.1038/s41467-017-02698-4. View

14.

Zhang L, Lovinger G, Edelstein E, Szymaniak A, Chierchia M, Morken J . Catalytic conjunctive cross-coupling enabled by metal-induced metallate rearrangement. Science. 2016; 351(6268):70-4. PMC: 5510870. DOI: 10.1126/science.aad6080. View

15.

Rono L, Yayla H, Wang D, Armstrong M, Knowles R . Enantioselective photoredox catalysis enabled by proton-coupled electron transfer: development of an asymmetric aza-pinacol cyclization. J Am Chem Soc. 2013; 135(47):17735-8. DOI: 10.1021/ja4100595. View

16.

Tarantino K, Liu P, Knowles R . Catalytic ketyl-olefin cyclizations enabled by proton-coupled electron transfer. J Am Chem Soc. 2013; 135(27):10022-5. DOI: 10.1021/ja404342j. View

17.

Molander G, Harris C . Sequencing Reactions with Samarium(II) Iodide. Chem Rev. 1996; 96(1):307-338. DOI: 10.1021/cr950019y. View

18.

Snider B . Manganese(III)-Based Oxidative Free-Radical Cyclizations. Chem Rev. 1996; 96(1):339-364. DOI: 10.1021/cr950026m. View

19.

Creutz S, Lotito K, Fu G, Peters J . Photoinduced Ullmann C-N coupling: demonstrating the viability of a radical pathway. Science. 2012; 338(6107):647-51. DOI: 10.1126/science.1226458. View

20.

Hart D . Free-radical carbon-carbon bond formation in organic synthesis. Science. 1984; 223(4639):883-7. DOI: 10.1126/science.223.4639.883. View