- Ruthenium-Catalyzed Selective Addition of Carboxylic Acids to Alkynes.A Novel Synthesis of Enol Esters
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Carboxylic acids react with alkynes in the presence of a catalytic amount of bis(ν5-cyclooctadienyl)ruthenium/trialkylphosphine/maleic anhydride in toluene at 60-80 deg.C to give enol esters having a terminal methylene group in good to excellent yields with high regioselectivity.The deuterium distributions in the products of the reaction of acetic acid-d with 1-hexyne and ethyl propargyl carbonate were examined.Kinetic measurments revealed that the rate has first-order dependence on carboxylic acid, alkyne, and the initial concentration of the ruthenium catalyst.
- Mitsudo, Take-aki,Hori, Yoji,Yamakawa, Yasushi,Watanabe, Yoshihisa
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p. 2230 - 2239
(2007/10/02)
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- Process for the preparation of unsaturated ketones
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Ketones, which are intermediates in the synthesis of vitamin A or perfumes, and have the general formula: EQU1 wherein R1 is hydrogen or C1-10 hydrocarbon, R2 and R3 are hydrogen or C1-4 alkyl, R4 and R5 are hydrogen or together form a --CH2 --CH2 --C(CH3)2 -- group, R6 and R7 are hydrogen or C1-10 hydrocarbon, or together with the carbon atom to which they are joined form a hydrocarbon ring of up to 10 carbons, or EQU2 forms a hydrocarbon ring of up to 10 carbons joined through R6 and R8 or R7 and R8, R8 is hydrogen or C1-10 hydrocarbon and n is 0-6, are prepared by reacting an unsaturated halide of formula EQU3 wherein X is halogen, with an enol ester of formula EQU4 wherein R9 is C1-20 hydrocarbon, in the presence of a metal catalyst.
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