APPLICATION OF THE FELKIN REACTION; NICKEL-INDUCED CONVERSION OF CARBON-OXYGEN INTO CARBON-CARBON BONDS

[摘要] The bis(triphenylphosphine)nickel dichloride-catalyzed reaction of 1-vinylcyclohexanol with phenylmagnesium bromide produced 1-penyl-1-vinylcyclohexane as the major product. An analogous product was obtained with 1-hexynylmagnesium bromide and this allylic alcohol, while the employment of trimethylsilylethynylmagnesium bromide led to substitution at the opposite terminus of the allyl system, yielding trimethylsilylethynylethylidenecyclohexane. Vinylmagnesium bromide initiated a disproportionation reaction of 1-vinylcyclohexanol which was investigated through deuterium labeling experiments. An intramolecular variation of these reactions was carried out with A yielding tricycles B. Indolymagnesium halides could be involved in these reactions as exemplified by the conversion of indolylmagnesium iodide to 3-allylindole in the presence of allyl alcohol, and to C and D in the presence of dimethylallyl alcohol. A reaction between skatole-derived Grignard reagent and allyl alcohol led to 2-allyl-3-methylindole. The nickel-catalyzed reaction of phenylmagnesium bromide with cyclohex-2-en-1-ol and 1-isopropenylcyclohexanol yielded 1-phenyl-cyclohex-2-ene and 1-phenyl-1-isopropenylcyclohexane, respectively. Both methylmagnesium, and phenylmagnesium bromides reacted with 1,3-dimethylcyclohex-2-en-1-ol to produce largely bi-1,3-dimethylcyclohexenyl. In a nickel catalyzed reaction of methylmagnesium and phenylmagnesium bromides with E, 1-isopropenylcyclohexanol and F were produced, respectively. Nickel-catalyzed substitution of the alkoxy groups of 1-methoxycyclohexene, 1-methoxy-4-tert-butylcyclohexene, 4-methoxyheptene, 1-methoxyheptene, dihydropyran, and 2-methoxynaphthalene by the alkyl or aryl groups of Grignard reagents could also be effected. Enamines, enolates, and highly hindered enol ethers proved ineffective in the latter process. An analysis of the stereochemistry associated with these substitutions revealed the original enol ether stereochemistry to be retained in most cases. A catalytic cycle explaining the enol ether substitution process is proposed.

[发布机构] Rice University