Indium-Mediated Intermolecular Alkyl Radical Addition to Electron-Deficient CN Bond and CC Bond in Water

Abstract

[reaction: see text] The intermolecular alkyl radical addition to imine derivatives was studied in aqueous media by using indium as a single-electron-transfer radical initiator. The one-pot reaction based on radical addition to glyoxylic hydrazone provided a convenient method for preparing the alpha-amino acids. The indium-mediated radical addition to an electron-deficient C=C bond also proceeded effectively to provide the new carbon-carbon bond-forming method in aqueous media.

Indium-mediated radical addition of perfluoroalkyl iodide in water

“…Indium has been demonstrated to be an efficient and promising metal for mediating organic reactions in aqueous media [19][20][21][22][23]. Indium-mediated carbon-carbon bond-forming reactions in aqueous media have been of great importance both economically and environmentally.…”

“…Indium-mediated carbon-carbon bond-forming reactions in aqueous media have been of great importance both economically and environmentally. Recently, Naito and co-workers reported the addition of an indium-mediated alkyl radical to an electrondeficient C5 5N bond or C5 5C bond [23]. However, the addition of an indium-mediated perfluoroalkyl radical to C5 5C bonds has yet to be studied.…”

Development of New Synthetic Reactions for Nitrogen-Containing Compounds and Their Application

“…61) Thus we investigated indium-and aqueous-mediated radical addition reaction to oxime ethers 28 and hydrazones 52 and found a novel synthetic method for a-amino and a-hydrazino acids. The result that practically no reaction of 28 occurred in the absence of water suggests that water is important for the activation of indium and for the proton-donor to the resulting amide anion C. 62) A plausible reaction pathway involves the SET reaction twice, as shown in Chart 19. Furthermore, the tolerance of hydrazone to the aqueous media provided practical one-pot synthesis of a-hydrazino acids and esters.…”

Recent Advances in Free Radical Chemistry of C-C Bond Formation in Aqueous Media: From Mechanistic Origins to Applications

“…Indeed, it appears that indium is the most reactive and effective metal for such reactions. The indium mediated radical additions to an electron deficient C=C bond also proceeded effectively to provide the new carbon-carbon bond forming method in aqueous media (Scheme 12) [48].The carbon-nitrogen double bond has emerged as a radical acceptor, and thus several intermolecular radical additions reactions have been recently investigated in organic solvents [27,49]. A variety of 1,3-dicarbonyl compounds have been alkylated successfully using allyl bromide or allyl chloride in conjunction with either tin or indium (Scheme 10).…”

“…As part of environmentally benign synthetic reaction in aqueous media [48,50,59,60] employing imines as a substrate, the zinc-mediated radical addition to the glyoxylic oxime ethers and hydrazones for asymmetric synthesis of aamino acids, have been reported. The zinc-mediated isopropyl radical addition to achiral glyoxylic oxime ether (shown in Scheme 16), in aqueous media (sat.…”