scholarly journals C-Acetylation of Ketones

1974 ◽  
Vol 52 (8) ◽  
pp. 1379-1380 ◽  
Author(s):  
Stuart Nicholas Huckin ◽  
Larry Weiler
Keyword(s):  
Good Yield ◽  
New Method ◽  
Keto Esters

The action of 2 equiv. of methyllithium on the monoanion of simple β-keto esters gives the β-diketone in good yield. This represents a facile and new method to achieve the C-acylation of a ketone.

Me3Ga-Mediated Addition of Acetylenes to α-Keto Esters: A New Method for the Synthesis of α-Hydroxy Esters

Synlett ◽  
2011 ◽  
Vol 2011 (14) ◽  
pp. 2039-2042 ◽  
Author(s):  
Chengjian Zhu ◽  
Yixiang Cheng ◽  
Honglai Jiang ◽  
Aijun Lin ◽  
Hao Peng ◽  
...  
Keyword(s):  
New Method ◽  
Keto Esters ◽  
Hydroxy Esters

scholarly journals Palladium-catalyzed alkylation of unactivated olefins

2004 ◽  
Vol 76 (3) ◽  
pp. 671-678 ◽  
Author(s):  
Ross A. Widenhoefer
Keyword(s):  
Good Yield ◽  
Catalytic Amount ◽  
Outer Sphere ◽  
Deuterium Labeling ◽  
Carbon Nucleophiles ◽  
Keto Esters ◽  
Reactive Carbon ◽  
Aryl Ketones ◽  
Palladium Catalyzed ◽  
Hydride Elimination

The reaction of a 3-butenyl β-diketone with a catalytic amount of PdCl2(CH3CN)2 in dioxane at room temperature led to olefin hydroalkylation and formation of the corresponding 2-acylcyclohexanone in good yield as a single regioisomer. Deuterium-labeling experiments for the hydroalkylation of 7-octene-2,4-dione were in accord with a mechanism involving outer-sphere attack of the pendant enol on a palladium-complexed olefin to form a palladium cyclohexyl species, followed by palladium migration via iterative β-hydride elimination/addition and protonolysis from a palladium enolate complex. In comparison to a 3-butenyl β-diketone, reaction of a 4-pentenyl β-diketone with a catalytic amount of PdCl2(CH3CN)2 in the presence of CuCl2 led to oxidative alkylation and formation of the corresponding 2-acyl-3-methyl-2-cyclohexenone in good yield as a single isomer. Unactivated olefins tethered to less reactive carbon nucleophiles such as β-keto esters, α-aryl ketones, and even dialkyl ketones underwent palladium-catalyzed hydroalkylation in the presence of Me3SiCl or HCl to form the corresponding cyclohexanones in moderate-to-good yield with high regioselectivity.

The Retro-Michael Reaction of 1,5-Dicarbonyl Compounds: Scope and Limitation

1999 ◽  
Vol 64 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Jian-Xin Wang ◽  
Tong-Shuang Li
Keyword(s):  
Good Yield ◽  
Steam Distillation ◽  
Michael Reaction ◽  
Glass Wool ◽  
Dicarbonyl Compounds ◽  
Keto Esters ◽  
Tricyclic Compounds ◽  
Keto Acids

Under catalysis of NaOH or KOH adsorbed on glass wool and by using steam distillation, (20R,S)-4,4,5,14-tetramethyl-18,19-dinor-13,17-seco-5β,8α,9β,10α,14β-cholestane-13,17-dione (1) and 3,14-dioxo-14,15-seco-5α-cholestan-15-al (4) gave good yield (>59%) of the corresponding tricyclic compounds (8a, 8b and 10a) via a retro-Michael reaction at 250 °C. While 5-oxo-4-nor-3,5-secocholestan-3-oic acid (6) and ethyl 5-oxo-4-nor-3,5-secocholestan-3-oate (7) afforded low yield (<15%) of the retro-Michael cleavage products (12a, 12b) at the same conditions. Thus, the retro-Michael reaction worked well for 1,5-diketones and 1,5-keto aldehydes but gave poor yield for 1,5-keto esters and 1,5-keto acids.

Preparation of Organometallic and Silyl Complexes of Palladium(II) via [PdCl(SnCl3)L2], where L = PPh3, P(p-Tol)3

2004 ◽  
Vol 69 (7) ◽  
pp. 1464-1471 ◽  
Author(s):  
Małgorzata Noskowska ◽  
Wojciech Duczmal
Keyword(s):  
Reaction Mechanism ◽  
Good Yield ◽  
New Method ◽  
Organohalogen Compound ◽  
Silyl Complexes

A new method for preparing organometallic and monosilyl complexes of Pd(II), based on the interaction between [PdCl(SnCl3)L2] (L = PPh3 or P(p-Tol)3) and appropriate organohalogen compound or chlorosilane has been developed. The products without tin have been obtained with good yield (85-97%). The reaction mechanism has been proposed on the basis of kinetic and chemometric investigations of the reaction between [PdCl(SnCl3)(PPh3)2] and Me2SiCl2.

scholarly journals Synthetic routes to 1,3-divinyl cyclobutanes

1987 ◽  
Author(s):  
Σωτήριος Ιερόπουλος
Keyword(s):  
Metal Complexes ◽  
Good Yield ◽  
Room Temperature ◽  
Wittig Reaction ◽  
Organic Reactions ◽  
New Method ◽  
Cycloaddition Reactions ◽  
Facile Synthesis ◽  
Synthetic Routes ◽  
Ketone Ester

The chemistry of the cyclobutadiene metal complexes of the last decade is reviewed. Emphasis is given to the organic reactions involving the cyclobutadiene ligand. Dichoro, dimethyl, and diphenyl ketenes were used in [2+21-cycloaddition reactions with 1,3-dienes, which included 1-vinyl cyclohexene, 2-triethylsilylbuta-l,3-diene and 1- and 2- trimethylsilyloxybuta-1,3-dienes. Thecycloadditions were rarely found to be regiospecific and nearly always low yielding. The produced cyclobutanones were very often unstable. 2,2-Diphenyl-3-(1'-triethylsilyl-1'-ethenyl) cyclobutanone was prepared but it was found not to produce the expected 1,3-divinyl cyclobutan-l-ol when treated with vinylmagnesium bromide. 2,2-Dimethyl and 2,2-diphenyl-3-ethoxy cyclobutanones were prepared and their reactions with vinylmagnesium bromide and methyl lithium were investigated. Ethyl 4,4-diphenylbut-3-enoate was formed when 2,2-diphenyl-3-ethoxy cyclobutanone was treated with vinylmagnesium bromide. As well as the above ester, the same cyclobutanone gave 5,5-diphenylpent4-en-2-one when treated with methyl lithium. 2,2-Dimethyl3-ethoxy cyclobutanone gave the expected alcohols when reacted with the same two reagents. 1-(11-Phenyl-2'-propenyl)-2,2-dimethyl-3-vinyl cyclobutane was synthesised starting from a-pinene. The best route was found to involve the preparation of pinonic aldehyde by ozonolysis of q-pinene. The aldehyde was reduced to pinonic alcohol which was then converted to pinonic iodide by treatment with triphenylphosphine and iodine. The iodide was dehydrohalogenated by a new method, described in chapter six of the thesis, to givel-acetyl-2,2-dimethy1-3-vinyl cyclobutane. A subsequent Wittig reaction gave the desired divinyl cyclobutane. Finally, the development of a new methodology is described for the dehydrohalogenation of primary bromides and iodides. It involves a novel, facile synthesis of tetrakis(triphenylphosphine) nickel. The primary halide is mixed with 1,8-diazabicyclo[5.4.0lundec-7-ene and the mixture added to the low valent nickel reagent. The alkene was formed in good yield after twelve hours of stirring at room temperature under argon. The reaction was applied to a few halides and it was found to be compatible with alcohol, ketone, ester, and ether groups.

Human Prothrombin: A New Method of Preparation from a Single Individual

1973 ◽  
Vol 30 (03) ◽  
pp. 425-436 ◽  
Author(s):  
Richard Benarous ◽  
Dominique Labie ◽  
François Josso
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Amino Acid Analysis ◽  
Good Yield ◽  
New Method ◽  
Single Individual ◽  
Single Chain ◽  
Simple Method ◽  
Terminal Residue ◽  
Sds Electrophoresis

SummaryA simple method for purification of human prothrombin from ACT) plasma of one single individual is described. This method is based on three steps :1. isolation of crude prothrombin complex by barium citrate adsorption;2. first purification by hydroxyapatite chromatography;3. further purification by DEAE Sephadex chromatography.The final product was obtained with a good yield and exhibited less than 5 p. cent contamination. The human purified prothrombin obtained in this way displays :– one single chain by SDS electrophoresis,– a molecular weight of 75,000-80,000 daltons,– a pi value pH 4.4 by electrofocusing,– Alanine as थ terminal residue.Amino-acid analysis is reported.

Titanium-induced cyclization of keto esters: a new method of cycloalkanone synthesis

1983 ◽  
Vol 105 (6) ◽  
pp. 1660-1661 ◽  
Author(s):  
John E. McMurry ◽  
Dennis D. Miller
Keyword(s):  
New Method ◽  
Keto Esters

Synthesis of (±)-karahana ether and a (±)-labdadienoic acid by the electrophilic cyclization of epoxy allylsilanes

1986 ◽  
Vol 64 (3) ◽  
pp. 584-596 ◽  
Author(s):  
Rosemary J. Armstrong ◽  
Larry Weiler
Keyword(s):  
Good Yield ◽  
Lewis Acids ◽  
Electrophilic Cyclization ◽  
Keto Esters

The epoxy allysilanes 7 and 16 were synthesized by stereoselective routes from β-keto esters and cyclized with Lewis acids in good yield. The monocyclic product from 7 was converted into (±)-karahana ether (10), and the bicyclic product from 20 was used in a synthesis of the 3-hydroxylabdadienoic acid 24b.[Formula: see text]

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