ChemInform Abstract: Stereoselective Hydrogenation of α-Sulfinyl Radical Generated from Alkyl Radical Addition to α-(1-Hydroxyethyl)vinyl Sulfoxide.

Abstract Sulfinyl radicals – one of the fundamental classes of S-centered radicals – have eluded synthetic application in organic chemistry for over 60 years, despite their potential to assemble valuable sulfoxide compounds. Here we report the successful generation and use of sulfinyl radicals in a dual radical addition / radical coupling with unsaturated hydrocarbons, where readily-accessed sulfinyl sulfones serve as the sulfinyl radical precursor. The strategy provides an entry to a variety of previously inaccessible linear and cyclic disulfurized adducts in a single step, and demonstrates excellent tolerance to an extensive range of hydrocarbons and functional groups. Experimental and theoretical mechanistic investigations suggest that these reactions proceed through sequential sulfonyl and sulfinyl radical addition.

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Controlling alkyne reactivity by means of a copper-catalyzed radical reaction system for the synthesis of functionalized quaternary carbons

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.16.45 ◽

2020 ◽

Vol 16 ◽

pp. 502-508

Author(s):

Goki Hirata ◽

Yu Yamane ◽

Naoya Tsubaki ◽

Reina Hara ◽

Takashi Nishikata

Keyword(s):

Alkyl Radical ◽

Copper Catalyst ◽

Radical Reaction ◽

Reaction System ◽

Radical Addition ◽

Terminal Alkyne ◽

Multiple Bonds ◽

Complex Molecules ◽

Reaction Patterns ◽

Tertiary Alkyl

A terminal alkyne is one of the most useful reactants for the synthesis of alkyne and alkene derivatives. Because an alkyne undergoes addition reaction at a C–C triple bond or cross-coupling at a terminal C–H bond. Combining those reaction patterns could realize a new reaction methodology to synthesize complex molecules including C–C multiple bonds. In this report, we found that the reaction of 3 equivalents of terminal alkyne 1 (aryl substituted alkyne) and an α-bromocarbonyl compound 2 (tertiary alkyl radical precursor) undergoes tandem alkyl radical addition/Sonogashira coupling to produce 1,3-enyne compound 3 possessing a quaternary carbon in the presence of a copper catalyst. Moreover, the reaction of α-bromocarbonyl compound 2 and an alkyne 4 possessing a carboxamide moiety undergoes tandem alkyl radical addition/C–H coupling to produce indolinone derivative 5.

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Heterocycle synthesis via radical reactions

Pure and Applied Chemistry ◽

10.1351/pac200880040717 ◽

2008 ◽

Vol 80 (4) ◽

pp. 717-726 ◽

Cited By ~ 20

Author(s):

Takeaki Naito

Keyword(s):

Total Synthesis ◽

Heterocyclic Compounds ◽

Alkyl Radical ◽

Radical Addition ◽

Synthetic Method ◽

Asymmetric Total Synthesis ◽

Heterocycle Synthesis ◽

Leaving Group ◽

Martinellic Acid ◽

Type Radical

A novel synthetic method for the preparation of nitrogen-containing heterocycles via the route involving domino-type radical addition/cyclization reaction of oxime ethers is described. Alkyl radical addition/cyclization of oxime ethers carrying an appropriate leaving group proceeded smoothly to form the alkylated nitrogen-containing heterocyclic compounds. Additionally, tin-mediated radical addition/cyclization/elimination (RACE) reaction of oxime ethers is newly found and successfully applied to an asymmetric total synthesis of (-)-martinellic acid.

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