133055-13-7Relevant articles and documents
PHOTOSTIMULATED REACTIONS OF NEOPENTYL IODIDES WITH CARBANIONS IN DMSO BY THE SRN1 MECHANISM
Penenory, Alicia B.,Rossi, Roberto A.
, p. 605 - 610 (2007/10/03)
Neopentyl iodide, 1, reacted under photostimulation with several carbanionic nucleophiles in DMSO.With acetone enolate ion only reduction and dimerization occured, but good yields of substitution products have been obtained with acetophenone, 5, and anthrone, 9, anions as nucleophiles.Nitromethane anion, 7, does not react with 1 under irradiation, but good yields of the substitution products are obtained when the photostimulated reaction is carried out in the presence of acetone enolate ions (entrainment reaction).Inhibition experiments by p-dinitrobenzene and by the radical trap TEMPO, suggest that these reactions occur by the SRN1 mechanism of nucleophilic substitution.The photostimulated reaction of 1,3-diiodo-2,2-dimethylpropane, 15, with 5 gave the disubstitution product 17 and the reduced monosubstitution product 18.It has been found that the monosubstitution product 16 (in which iodine is retained) is not an intermediate of these reactions. 1-iodoadamantane, 12, is more reactive (ca. 4.9 times) than 1 in competitive experiments toward 5 and under photostimulation.
Nickel-Mediated Cross-Coupling of Unactivated Neopentyl Iodides with Organozincs
Park, Kwangyong,Yuan, Kaixu,Scott, William J.
, p. 4866 - 4870 (2007/10/02)
(dppf)NiCl2 catalyzes the cross-coupling of unactivated primary neopentyl iodides with diorganozinc reagents.The zinc nucleophiles are formed by the treatment of ZnCl2*dioxane with 2 mol equiv of a Grignard reagent in an etheral solvent.The cross-coupling works optimally for diorganozincs formed from aryl chlorides or CH3MgCl.Use of aryl bromides can cause reduction and/or reductive dimerization of the electrophile.The analogous reaction with (CH3)2CuMgCl in either the presence or the absence of Group 10 metal catalysts failed to afford reasonable yields of cross-coupled products.The diorganozinc methodology overcomes many of the side reactions observed with the (dppf)NiCl2-mediated cross-coupling of Grignard reagents.
Nickel-catalyzed cross-coupling of unactivated neopentyl iodides with Grignard reagents
Yuan,Scott
, p. 189 - 192 (2007/10/02)
Primary neopentyl iodides react with aryl Grignard reagents in the presence of 10 mol% (dppf)NiCl2 to give the cross-coupled product.
On the Mechanism of the Reduction of Primary Halides with Grignard Reagents in the Presence of (dppf)PdCl2 or (dppf)Pd(0)
Yuan, Kaixu,Scott, William J.
, p. 6188 - 6194 (2007/10/02)
Reaction of primary alkyl halides with Grignard reagents in the presence (dppf)PdCl2 or (dppf)Pd(0) leads to reduction of the halide.The mechanism of the reduction is dependent on the solvent and the Grignard reagent.In tetrahydrofuran, reduction is independent of palladium.The alkyl halide is largely reduced by β-hydride transfer from the Grignard reagent.Competing with hydride transfer is a halogen-metal exchange reaction, which converts the alkyl halide into the corresponding Grignard reagent.Protonation of reaction mixture then gives the observed products.Grignard reagents that do not possess β-hydrogens undergo the halogen-metal exchange exclusively, but still lead to reduction of the alkyl halide.At subambient temperatures and in diethyl ether, reduction of primary alkyl halides with Grignard reagents in the absence of palladium catalysts is very slow.That reduction which does occur is almost exclusively the product of β-hydride transfer.The addition of (dppf)PdCl2 markedly accelerates the rate of reduction of alkyl halides in diethyl ether.The catalytic effect is proposed to occur through a catalytic cycle involving oxidative addition of the alkyl halide, hydride-transfer, and reductive-elimination steps.The order of the first two steps remains unclear.
