Heptamethyltrisilane-2-thiol-mediated free-radical-chain reduction of organic halides

Abstract

Free-radical-chain reduction of organic halides is accomplished with heptamethyltrisilanethiol, a reducing agent combining the good hydrogen donating ability of a thiol and the excellent halogen abstracting properties of a silyl radical.

Tin Hydride Substitutes in Reductive Radical Chain Reactions

“…The silylated thiols 46 and 47 can be used as tin hydride substitutes in reductive radical chain reactions. 98,99 The thiol moiety acts as the reducing group in these reagents. Thus, the reduction of a C-radical with thiol 47 affords the corresponding alkane and the thiyl radical 48, which undergoes a 1,2-silyl group migration to generate silyl radical 49 (Scheme 16).…”

Homolytic Substitution: A Molecular Ménage à Trois

“…Note the analogy with the (Me 3 Si) 2 Si(Me)SH-mediated reductions of alkyl halides. 8 A further development of this process deploys allyl, allenyl, or alkynyl cobaloximes, 9,10 The most successful reagents are organobis(dimethylglyoximato)pyridines (6) (Scheme 2), which react with electrophilic radicals to afford allyl compounds together with Co II (dmgH) 2 py (7). The displaced cobalt complex 7 is instrumental in generation of the initial radical in the second stage of chain propagation.…”

Flight from the Tyranny of Tin: The Quest for Practical Radical Sources Free from Metal Encumbrances

“…The electronegativity of sulfur, and the possibility of 3p ± 3p overlap between silicon and sulfur atoms, was expected to reduce the SiÀH bond strength of tri(alkyl- 3 SiH. [52] Heptamethyltrisilane-2-thiol [53] (16 a) and tris(trimethylsilyl)silane-2-thiol [54] (16 b) possess thiol groups which readily donate hydrogen atoms to C-centered radicals to afford thiyl radicals 17 (Scheme 4). These reagents then take advantage of the rapid Scheme 4.…”