- Ruthenium Complex-Catalyzed Carbonylation of Allylic Compounds
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Allylic alkyl carbonates are carbonylated under 40 atm of carbon monoxide at 100-120 deg C in the presence of a catalytic amount of Ru3(CO)12/1,10-phenanthroline to give α,β- or β,γ-unsaturated esters in good to high yields.For example, cinnamyl methyl carbonate afforded the corresponding β,γ-unsaturated esters, methyl trans-4-phenyl-3-butenoate (1) in 93percent yield.The regioselectivity in the carbonylation of crotyl methyl carbonate is unusual and it depends on the carbon monoxide pressure.The more sterically hindered carbon (γ-carbon) is predominantly carbonylated at 20-50 atm.When the reaction of cinnamyl methyl carbonate was performed at elevated temperature (150 deg C) without 1,10-phenanthroline, the dimer of 1, dimethyl 3-benzyl-2-(trans-2-phenylvinyl)glutarate, was obtained in 56percent yield.In the presence of secondary amines, allylic alkyl carbonates were carbonylated mainly at α-carbon to give α,β- or β,γ-unsaturated amides in high yields.
- Mitsudo, Take-aki,Suzuki, Nobuyoshi,Kondo, Teruyuki,Watanabe, Yoshihisa
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p. 7759 - 7765
(2007/10/02)
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- Cobalt-Catalyzed Photochemical Carbonylation of Allylic Amines
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Allylic amines are carbonylated at room temperature in the presence of cobalt catalysts under UV irradiation.With allylamine, 2-pyrrolidone, N,N'-diallylurea, and N-allyl-3-butenamide were obtained.The photochemical cleavage of C-N bond of amines coordinated to cobalt metals was suggested.
- Mori, Sadayuki,Matsuyoshi, Hiroaki,Kudo, Kiyoshi,Sugita, Nobuyuki
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p. 1397 - 1400
(2007/10/02)
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- Reactions of π-allylic complexes of palladium with methyl formate
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The reaction of methyl formate with various π-allylic palladium complexes is reported. Unsaturated carboxylic acid esters are formed in high yield and selectivity. A comparison of the reactivity of methyl formate with that of the hydroesterification subst
- Keim,Becker,Kraneburg,Greven
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- Cyclopropanation of α,β-Unsaturated Carbonyl Compounds and Nitriles with Diazo Compounds. The nature of the Involvement of Transition-Metal Promoters
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In the presence of molybdenum hexacarbonyl or molybdenum(II) acetate, ethyl diazoacetate and α-diazoacetophenone react with α,β-unsaturated carbonyl compounds and nitriles to form derivative cyclopropane and vinyl CH insertion products.In the absence of these promoters or in the presence of catalytic amounts of pyridine, 2-pyrazolines are the major or sole reaction products.Kinetic investigations for reactions between ethyl diazoacetate and α,β-unsaturated esters and nitriles in the presence of Mo(CO)6, Mo2(OAc)4, or pyridine demonstrate the absence of any significant influence by these molybdenum promoters or pyridine on the rates and activation parameters for ethyl diazoacetate decomposition.Representative 1-pyrazolines have been synthesized and observed to undergo dinitrogen extrusion without apparent influence by molybdenum promoters.The composite results suggest that these molybdenum promoted reactions occur by dipolar cycloaddition of diazocarbonyl compounds to α,β-unsaturated systems and that the derivative 1-pyrazoline intermediates undergo dinitrogen extrusion to form the observed cyclopropane and vinyl CH insertion products.Molybdenum promoters function to inhibit competitive tautomerization of the initially formed cycloaddition products.The relative effectiveness of a broad selection of transition-metal compounds in directing reactions between ethyl diazoacetate and α,β-unsaturated esters and nitriles to cyclopropane products is described.The cycloaddition / dinitrogen extrusion pathway is presented as a viable mechanism for cyclopropanation of α,β-unsaturated systems by diazo compounds, even for reactions performed in the presence of traditional cyclopropanation catalysts.
- Doyle, Michael P.,Dorow, Roberta L.,Tamblyn, William H.
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p. 4059 - 4068
(2007/10/02)
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