Evidence for single electron transfer in the reaction of alkoxides with alkyl halides

Evidence for a radical process in the reaction of lithium alkoxides with alkyl iodides was obtained by the observation of cyclization of appropriate radical probes, by the trapping of radicals, and by EPR spectroscopic observations relating to the one electron donor properties of alkoxides.     

Evidence for single electron transfer in the reaction of a lithium enolate with a primary alkyl iodide

Evidence for a radical process in the reaction of the lithium enolate of propiophenone with a primary alkyl iodide was obtained by the observation of cyclization of an appropriate radical probe, by the trapping of the radical intermediate and by the comparison of the relative rates of reactions of the probe alkyl iodide with the corresponding bromide and tosylate.     

Evidence for a single electron transfer mechanism in reactions of lithium diorganocuprates with organic halides

It has been demonstrated by means of spectroscopic studies involving cyclizable alkyl halides that lithium dimethylcuprate can react with organic halides by a single electron transfer pathway.     

Spectroscopic evidence for the reduction of alkyl halides by metal hydrides via a single electron transfer mechanism

This report provides spectroscopic evidence to support a single electron transfer pathway to describe the reaction of metal hydrides with alkyl halides by direct EPR observation of the radical formed in the reaction.     

Evidence for single electron transfer in the reactions of organometallic compounds with 2,3,3-trimethyl-2-butyl peroxybenzoate

Utilization of a triptoxy radical probe in the reactions of organometallic compounds with 2,3,3-trimethyl-2-butyl peroxybenzoate indicates that the radical character of the reaction decreases in the order $\text{n}$-BuLi > $\text{n}$-BuMgCl > PhMgBr.     

Cobalt-catalyzed Heck-type reaction of alkyl halides with styrenes

A cobalt complex, CoCl2[1,6-bis(diphenylphosphino)hexane], catalyzes an alkylation reaction of styrenes in the presence of Me3SiCH2MgCl in ether to yield beta-alkylstyrenes. A variety of alkyl halides including alkyl chlorides can be employed as an alkyl source. A radical mechanism is strongly suggested for this alkylation reaction.     

Copper-catalyzed reaction of alkyl halides with cyclopentadienylmagnesium reagent

Treatment of alkyl halides, including tertiary alkyl bromides, with cyclopentadienylmagnesium bromide in the presence of a catalytic amount of copper(II) triflate yielded the corresponding cyclopentadienylated products in high yields. The following hydrogenation of the products provided alkyl-substituted cyclopentanes.     

Distannane mediated reaction of N-acyliminium ion pools with alkyl halides. A chain mechanism involving radical addition followed by electron transfer

Hexabutyldistannane was found to be an effective mediator allowing the reaction of N-acyliminium ion pools with alkyl halides. A chain mechanism involving the addition of an alkyl radical generated from an alkyl halide to an N-acyliminium ion followed by the one-electron reduction of the resulting radical-cation by distannane was proposed.     

The effect of HMPA on the reactivity of epoxides,aziridines, and alkyl halides with organolithium reagents

A kinetic study of the effect of added HMPA cosolvent on the reaction of 2-lithio-1,3-dithiane (1), bis(phenylthio)methyllithium (2), and bis(3,5-bistrifluoromethylphenylthio)methyllithium (3) with methyloxirane (propylene oxide), N-tosyl-2-methylaziridine, and the several alkyl halides (BuCl, BuBr, BuI, allyl chloride) was carried out. Widely varied rate effects of HMPA on these SN2 substitutions were observed, ranging from >108 rate increases for 1 and butyl chloride to >103 rate decreases for 3 and methyloxirane. These reactions appear to go through separated ion pair intermediates, so a key effect is the ease of ion pair separation of the lithium reagent (3 > 2 > 1). Because 3 is already almost fully separated in THF, HMPA has no effect on the rate of halide substitution, but a large reduction is observed with the epoxide as substrate, a consequence of strong lithium assistance to the ring opening which is suppressed when excess HMPA is present. When ion pair separation is difficult (1), modest rate increases (104) are seen for epoxide opening, but very large increases are seen for aziridine (106) and alkyl halide reactions (108), for which lithium assistance is much less important. Reagent 2 shows more complicated behavior in reaction with the epoxide: 1-2 equiv of HMPA causes a small rate increase, while larger amounts cause a large rate decrease. Here the rate-accelerating effects of SIP formation are more nearly balanced with the rate-retarding effects of suppression of lithium catalysis.     

Structural and EPR characterisation of single electron and alkyl transfer products from reaction of dimethyl magnesium with bulky alpha-diimine ligands

Treatment of dimethylmagnesium with bulky alpha-diimine ligands provides either the biradical methyl-bridged complexes [(alpha-diimine-.)Mg+(mu-CH3)]2 via single electron transfer (SET), or the product of methyl transfer to an imine carbon atom depending upon conditions.     

The reaction of metallic mercury with alkyl halides in the presence of nucleophilic reagents

Russian Chemical Bulletin -