- Alkylation of alkenes: Ethylaluminum sesquichloride-mediated hydro-alkyl additions with alkyl chloroformates and di-tert-butylpyrocarbonate
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A general method for the hydro-alkyl addition to the nonactivated C=C double bond of alkenes using alkyl chloroformates (primary, secondary), 12, and di-tert-butylpyrocarbonate, 52, mediated by ethylaluminum sesquichloride (Et3Al2Cl3) has been developed. Reaction of 12 and 52, respectively, with Et3Al2Cl3 gives an alkyl cation which is added to the alkene; hydride transfer to the adduct carbenium ion or, if applicable, 1,2-H shift followed by hydride transfer from Et3Al2Cl3 to the rearranged adduct carbenium ion gives the saturated addition product. The reaction has been applied to 1-alkenes, 2-methyl-1-alkenes, internal double bonds, and to three cyclic alkenes. Special interest has been focused on alkylations of unsaturated fatty compounds, such as oleic acid (2), which are important renewable feedstocks. 2-Methylalkanes, 3-methylalkanes, 2,4-dimethylalkanes, 2,3-dimethylalkanes, 2,2,4-trimethylalkanes, cyclohexylalkanes, and carboxylic acids and esters with the respective branched alkyl chain have been synthesized with good to moderate yields.
- Biermann, Ursula,Metzger, Juergen O.
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p. 10319 - 10330
(2007/10/03)
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- Oxidative transformations of cyclohexane, methylcyclopentane, and pentane on treatment with superelectrophiles based on polyhalomethane and aluminum halides
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Cyclohexane and methylcyclopentane dimerize into dimethyldecalins on treatment with superelectrophilic systems containing polyhalomethanes (CBr4, CCl4, CHCl3) and aluminum halides (AlBr3, AlCl3). At 2
- Akhrem,Churilova,Vitt
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- Dehydration Studies of α- and β-Ionol. I With Hexamethylphosphoric Triamide
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α-Ionol (2) when heated under reflux with hexamethylphosphoric triamide gave principally one product (1'E)-6-(buta-1',3'-dienyl)-1,5,5-trimethylcyclohex-1-ene (4a) together with trace quantities of the (1'Z)-isomer (4b).Under similar conditions β-Ionol (3) gave as major products (6E,2'E)- and (6Z,2'E)-6-(but-2'-enylidene)-1,5,5-trimethylcyclohex-1-ene (1a) and (1b) together with smaller quantities of (1'E)-1-(buta-1',3'-dienyl)-6,6-dimethyl-2-mehtylenecyclohexane (8) and 1,1,6-trimethyl-1,2,3,4,5,6-hexahydronaphtalene (9).Minor products from this reaction includedthe isomeric trienes (1c) and (1d).Reaction pathways are suggested for the formation of all identified products.
- Whitfield, Frank B.,Sugowdz, Galina
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p. 591 - 600
(2007/10/02)
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