Alkene hydrogenated chloro

Our belief that carbocations are intermediates m the addition of hydrogen halides to alkenes is strengthened by the fact that rearrangements sometimes occur For example the reaction of hydrogen chloride with 3 methyl 1 butene is expected to produce 2 chloro 3 methylbutane Instead a mixture of 2 chloro 3 methylbutane and 2 chloro 2 methylbutane results... 

The addition of iodine monochloridc to 1,4,4-trifluorocyclobutene and l-chloro-2,3,3-trifluo-rocyclobutene appears to be controlled by similar polarity factors, i.e. the alkene carbons substituted with a fluorine atom are negative with respect to those substituted with either a hydrogen atom or a chlorine atom.13 The products, 3-chloro-2-iodo-l,l,2-trifluorocyclobutane (8a) and l,l-dichloro-2-iodo-2,3,3-trifluorocyclobutane (8b) were isolated in 80 and 45% yield, respectively. Their structures were established by NMR spectroscopy.13... 

Reaction of AT-fluorobis(trifluoromethylsulfonyl)amine (Id) with alkenes gives various products, depending on the reaction conditions and the structure of the substrate. In solvents of higher nucleophilicity such as water, acetic acid, aqueous hydrochloric acid, and 70 % hydrogen fluoride/pyridine, a-fluorohydrins or their acetates, a-chloro-fl-fluoroalkanes or a,/ -difluoroal-kanes, e.g. 14. are obtained.146 Reaction of styrene and ( >l-phenylpropene with Id in dich-loromethane/acetic acid gives l-acetoxy-2-fluoro-l-phenylethane and -propane, in 92 and 99 % yield, respectively, the latter product in a ratio (erythrojthreo) 1 l.146... 

Chloro complexes of ruthenium(II) were found to hydrogenate maleic and fumaric adds to succinic add slowly at 60-80 °C and normal pressure of hydrogen. Non-activated alkenes lead to the production of ruthenium metal. The structures of the species involved are unknown. The mechanism involves coordination of the alkene followed by heterolytic cleavage of hydrogen, giving a ruthenium(II) hydride as the second step.41... 

E. J. Allain, L. P. Hager, L. Deng, and E. N. Jacobsen, Highly enantioselective epoxidation of disubstituted alkenes with hydrogen peroxide catalyzed by chloro-peroxidase, J. Am. Chem. Soc. 1993, 115, 4415-4416. 

A-8. What two alkenes give 2-chloro-2-methylbutane on reaction with hydrogen chloride ... 

A simple example involves the reaction of the silyl ether 213, made from the corresponding 4-hydroxy-alkene by treatment with (bromomethyl)chloro-dimethylsilane, with tributyltin hydride and a radical initiator. Bromine abstraction and intramolecular cyclization with the double bond leads to the bicyclic 214, which upon oxidation with hydrogen peroxide gives the branched-chain 215 in an overall yield of 73% from the alcohol precursor of 213 (Scheme 21). When the sequence is conducted with the C-4 epimeric starting alcohol, the final product again has the hydroxymethyl group cis-related to the hydroxy group.217... 

Continued research on N-silyl-phospha-amidines and N,N-bis-silylated phosphaguanidines (5) led us to carbosilylated phos-phaalkenes. The various routes to trimethylsilylmethyl-chloro-phosphines and their conversion into carbosilylated phospha-alkenes is given in Scheme 4 (6). Interaction of these products with hydrogen chloride leads to Si2CH-PRCl and Si-CH2-PRC1, respectively. By HC1 abstraction from these products, the parent... 

As a rule, in nucleophilic additions to halogenated alkenes, the nucleophile always becomes attached to that carbon of the double bond that has lower electron density. In this case, back-donation of electrons by fluorine is stronger in the difluoromethylene group, and nitrogen therefore attacks the difluoromethylene group while proton adds to the other carbon. Because of the basicity of the reaction mixture, hydrogen fluoride is eliminated, and an imide fluoride, 3-chloro-2,3-difluoro-l-phenyl-1-aza-propene is formed ... 

Although reactions of hypophosphorous acid with aqueous solutions of RuX3 (X = Cl, Br, I) are claimed to give RuX in situ,22 2 further work in this area is now required. More recently, Ru1 chloro compounds of possible formula H[Ru2Cl3(DMA)2] have been isolated from reaction of RuC13 x-H20 with H2 in DMA these species are effective catalysts for hydrogenation of alkenes and unsaturated carboxylic acids.2283... 

In the presence of iron(III) chloride, the reaction of alkenes with sodium azide, iron(II) sulfate and hydrogen peroxide leads to /J-chloro azides, via the following mechanism8,9. 

These carbocation rearrangements are similar to those that occur dur- ing electrophilic additions to alkenes (Section 6.12). For example, the relatively unstable primary butyl carbocation produced by reaction of 1-chloro-butane with AICI3 rearranges to the more stable secondary butyl carbocation by shift of a hydrogen atom and its electron pair (a hydride ion, H ) from C2 to Cl. 1... 

---