1592-34-3Relevant academic research and scientific papers
Improved preparative route toward 3-arylcyclopropenes
Sherrill, William M.,Kim, Ryan,Rubin, Michael
, p. 8610 - 8617 (2008/12/21)
A convenient preparative protocol for the synthesis of various 3-arylcyclopropenes in a multigram scale is disclosed. Optimization of the reaction conditions and isolation procedures allowed for significant improvement of the chemical yields of these strained products. The described protocol was used for efficient preparation of a series of 3-methyl-3-arylcyclopropenes possessing different substituents in the aromatic ring. The effect of substitution in the aryl group on the stability of 3-arylcyclopropenes, as well as the corresponding precursors, is discussed.
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.
Solvent attack in grignard reagent formation from bromocyclopropane and 1-bromohexane in diethyl ether
Garst, John F.,Ungváry, Ferenc,Batlaw, Rajnish,Lawrence, Kathryn Easton
, p. 5392 - 5397 (2007/10/02)
In the reaction of magnesium with bromocyclopropane in diethyl ether at reflux, intermediate cyclopropyl radicals attack the solvent, giving cyclopropane (20-30 mol/100 mol of bromocyclopropane consumed) and solvent-derived products. In contrast, the similar reaction of 1-bromohexane gives no more than 0.5 mol of hexane from solvent attack by hexyl radicals. These data are consistent with calculations based on a mechanism (D Model) with freely diffusing intermediate radicals, in which cyclopropyl and hexyl radicals have similar reactivities in their conversions to Grignard reagents, but the cyclopropyl radical is approximately 1000 times as reactive toward the solvent as the hexyl radical.
Heterocyclic Polyfluoro-compounds. Part 32. Photochemical Reactions of 3-Chlorotetrafluoro- and 3,5-Dichlorotrifluoro-pyridines with Olefins, and their Photoreduction
Barlow, Michael G.,Haszeldine, Robert N.,Langridge, John R.
, p. 2520 - 2522 (2007/10/02)
Ethylene reacts photochemically with 3-chlorotetrafluoropyridine to yield 3-(2-chloroethyl)tetrafluoropyridine, and cyclo-pentene and -hexene yield the corresponding 3-cycloalkyltetrafluoropyridines.Photochemical reaction of cyclohexene with 3,5-dichlorotrifluoropyridine yields 3-chloro-5-cyclohexyltrifluoropyridine.The chlorine in 3-chlorotetrafluoropyridine, and one of the chlorines in 3,5-dichlorotrifluoropyridine, is readily reduced photochemically in solvents such as ethanol, diethyl ether, or acetone.
