56434-66-3Relevant academic research and scientific papers
Palladium-catalyzed methylation and arylation of sp2 and sp 3 C-H bonds in simple carboxylic acids
Giri, Ramesh,Maugel, Nathan,Li, Jiao-Jie,Wang, Dong-Hui,Breazzano, Steven P.,Saunders, Lindsey B.,Yu, Jin-Quan
, p. 3510 - 3511 (2007/10/03)
The use of preformed sodium carboxylates as substrates led to the first observation of facile Pd-insertions into sp3 β-C-H bonds in simple aliphatic acids. Consequently, Pd-catalyzed methylation and arylation of o-C-H bonds in benzoic acids and β-C-H bonds in aliphatic acids using either a phenylboronate, methylboronic acid, or ArI have been achieved via a C-H activation/C-C coupling sequence. Copyright
CYCLOPROPYL CARBANIONS DERIVED FROM ESTERS OF 2-PHENYLCYCLOPROPYLCARBOXYLIC ACIDS: CONFIGURATIONAL STABILITY AND REACTION WITH ELECTROPHILES
Feit, B. A.,Elser, R.,Melamed, U.,Goldberg, I.
, p. 5177 - 5180 (2007/10/02)
The base-catalyzed cis-trans isomerization of cis and trans-alkyl 2-phenylcyclopropylcarboxylates was studied in several aprotic solvents.It was found that contact ion-pairs of the derived carbanion lithium salts were configurationally more stable than the solvent-separated ones.Reaction of either the cis or the trans esters with Mel, and the reaction of the cis ester with Ph2C=O, resulted in the corresponding 1-substituted derivatives having cis geometry only.This was explained as due to steric hindrance to electrophilic attack exerted by the 2-phenyl group in the case of the trans substrate.The trans esters did not react with Ph2C=O.Inhibition of the trans-to-cis isomerization of the carbanion salt of the trans substrate in presence of Ph2C=O could lead to this result.
Deprotonation and Diastereoselective Alkylation of Methyl Cyclopropanecarboxylates
Reichelt, Ingrid,Reissig, Hans-Ulrich
, p. 3895 - 3914 (2007/10/02)
Using model compounds it is demonstrated when deprotonation of methyl cyclopropanecarboxylates leads to ester condensation products and when alkylation of the ester enolate can be performed.Under certain structural conditions (steric and electronic effect
Cyclopropanation of α,β-Unsaturated Carbonyl Compounds and Nitriles with Diazo Compounds. The nature of the Involvement of Transition-Metal Promoters
Doyle, Michael P.,Dorow, Roberta L.,Tamblyn, William H.
, p. 4059 - 4068 (2007/10/02)
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.
