A Novel Tin‐Free Procedure for Alkyl Radical Reactions

Abstract

Desulfuration as a source of alkyl radicals: The addition of alkylsulfanyl radicals to isocyanides gives the corresponding alkyl radicals. This methodology can replace the usual tin‐mediated radical procedures and allows for the generation of tertiary, secondary, and even nonstabilized primary radicals that can be used efficiently in reductive defunctionalizations and intermolecular additions to electron‐rich olefins (see scheme).

Proton-Coupled Electron Transfer in Organic Synthesis: Fundamentals, Applications, and Opportunities

“…In synthetic contexts, thiyl radicals are known to engage in a number of useful reactions [191][192][193][194][195][196][197][198], including C-H bond abstraction [197,[199][200][201][202][203]. Recently, MacMillan has demonstrated the capacity of catalytically generated thiyl radicals to cleave the C-H bond of benzylic ethers for radical coupling reactions ( Figure 27) to form diaryl methanols (a) [204] or β-amino ethers (b) [205].…”

Free‐Radical‐Based, Specific Desulfurization of Cysteine: A Powerful Advance in the Synthesis of Polypeptides and Glycopolypeptides

“…In summary, a mild and highly versatile free-radical [24] cysteine reduction method based on classical organic chemistry has been developed. This metal-free reduction protocol can accommodate a range of relevant functionality and will quite likely find broad application in complex peptide and glycopeptide settings.…”

Imidoyl Radicals in Organic Synthesis

“…Two of the authors of this review have recently used radical addition to isonitriles as the key step for a novel tinfree procedure for alkyl radical generation [67], which exploited the results obtained from their contemporaneous spectroscopic/kinetic investigation on the -fragmentation of thioimidoyl radicals [28]. This process is so fast that practically every kind of alkyl radical, from stabilized radicals to even primary, unstabilized alkyls, can be easily generated from 110 °C down to room temperature simply by reacting the corresponding thiols with tert-butyl isonitrile in the pres- ence of a radical initiator such as AIBN (80 or 110 °C) or triethylborane (room temperature).…”