597-76-2Relevant articles and documents
Hydrodehalogenation of 1,1-dibromocyclopropanes by Grignard reagents promoted by titanium compounds
Dulayymi, Juma'a R. Al,Baird, Mark S.,Bolesov, Ivan G.,Nizovtsev, Alexey V.,Tverezovsky, Viacheslav V.
, p. 1603 - 1618 (2007/10/03)
1,1-Dibromocyclopropanes are converted into the corresponding monobromocyclopropanes (as mixtures of stereoisomers where appropriate) by reaction with 1.0-1.3 mol equiv. of ethylmagnesium bromide and 2-10 mol% titanium isopropoxide for 90%). With ethylmagnesium bromide, the reaction occurs very slowly in the absence of catalyst; with methylmagnesium bromide, the reaction does occur in the absence of catalyst, but is only slightly promoted in the presence of titanium isopropoxide. Reactions with a number of other Grignard reagents are also discussed. In the case of phenethylmagnesium bromide, the major product containing the phenethyl-group is ethylbenzene, together with small amounts of styrene and ethyl 4-phenyl-2-butyl ether, a product of trapping of the solvent, ether. In other cases, relatively large amounts of a diether, formally derived by hydrogen ion adjacent to the ether oxygen followed by dimerisation, are isolated. No products were identified incorporating the cyclopropane and either the Grignard alkyl group or the solvent. Labelling studies indicate that the hydrogen introduced into the cyclopropane is not derived from either the α- or β-positions of the Grignard reagent. When the reduction is carried out with phenethylmagnesium bromide in d8-tetrahydrofuran both monobromides contain deuterium.
REACTION OF ALKYLMAGNESIUM HALIDES WITH CARBOXYLIC ESTERS IN THE PRESENCE OF TETRAISOPROPOXYTITANIUM
Kulinkovich, O.G.,Sviridov, S.V.,Vasilevskii, D.A.,Savchenko, A.I.,Pritytskaya, T.S.
, p. 250 - 253 (2007/10/02)
The reaction of carboxylic esters with a threefold molar excess of ethylmagnesium bromide in the presence of an equimolar amount of tetraisopropoxytitanium leads to the formation of the corresponding 1-substituted 1-cyclopropanols.Propyl-, butyl-,and 2-phenylethylmagnesium bromides enter into a similar reaction, leading to 1,2-disubstituted 1-cyclopropanols.
Stereochemistry of Aliphatic Carbocations, 13. Protonated Cyclopropanes as Intermediates in 1,2-Alkyl Shifts
Kirmse, Wolfgang,Loosen, Karin,Prolingheuer, Ernst-Christoph
, p. 129 - 141 (2007/10/02)
The nitrous acid deamination of 2-ethyl-1-methylbutylamine (10), 1,2-diethylbutylamine (35), and 2-ethyl-1-methylpentylamine (43) has been studied with respect to 1,2-alkyl shifts.Optically active and deuterated amines were employed whenever possible.The structure, configuration, and deuterium distribution of various products (e. g. 16 from 10, 40 and 48 from 35, 56 from 43) are most reasonably explained in terms of alkyl-bridged intermediates (corner-protonated cyclopropanes) which isomerize via proton shifts from corner to corner.The alternative interconversion of open ions via 1,3-H shifts is incompatible with our experimental results.
