Reactions ethyl magnesium bromide

Write the equation for the reaction of 1 hexyne with ethyl magnesium bromide as if it involved ethyl anion (CH3CH2 ) instead of CH3CH2MgBr and use curved arrows to represent the flow of electrons j... 

A method for generating a perfluoroarylmagnesium compound is the cleavage of a pentafluorophenyl-metal bond by a nucleophile such as ethyltnagnesium bromide As an example, tetrakis(pentafluorophenyl)tin on reaction with ethyl-magnesium bromide gives a series of products, one of which may result from pentafluorophenylmagnesium bromide [27] (equation 7)... 

Preparation of 3-Hexyne-2-ol A solution of ethyl magnesium bromide was prepared by the reaction of 229 g of ethyl bromide and 4B.6 g of magnesium in 750 ml of anhydrous ether. To the ether solution was then added with stirring a solution of 10B g of ethyl acetylene in 250 ml of cold anhydrous ether. The addition required approximately 3 hours, and the mixture was stirred and refluxed for a further period of 3V2 hours. Thereafter there was added to the reaction mixture a solution of BB g of freshly distilled acetaldehyde in 170 ml of anhydrous ether, over a period of about 45 minutes and at a temperature in the range of about -10° to 0°C. 

The interpretation put forward is not entirely satisfactory since the reaction does not seem to be dangerous when it is carried out with ethyl magnesium bromide. 

For the preparation of sterically crowded amides amino magnesium salts have been recommended for the reaction with imidazolides in order to increase the nucleophilicity of the amine moiety. Amino magnesium salts are prepared from the appropriate amines and ethyl magnesium bromide in tetrahydrofuran [90]... 

Tuulmets [Kinetics and Catalysis, 5 (59), 1964] has studied the kinetics of the reaction of ethyl magnesium bromide with pinacolin. He used a calorimetric technique to monitor the progress of the reaction. The overall temperature increase of the reaction mixture was less than a degree. Mixture temperatures were determined with a sensitive potentiometer. The data below... 

Phenylacetone, 54, 50 Phenylacetonitrile, 50, 20 Phenylacetylene, reaction with ethyl magnesium bromide,... 

Muller [76] has described a gas chromatographic method for the determination of tributyltin compounds in sediments. The tributyltin compounds are first converted to tributylmethyltin by reaction with ethyl magnesium bromide, and then analysed using capillary gas chromatography with flame photometric detection and gas chromatography-mass spectrometry. Tributyltin was found in samples of sediment and these results demonstrated that the technique has detection limits of less than 0.5pg L 1. 

In total, 29 phosphorus-containing chiral ligands of various structures were screened under the optimized y-selective conditions, but most of them gave little or no chiral induction. The four ligands 38a-d, all derived from (—)-TADDOL, depicted in Fig. 8.4 gave ees in excess of 30% in the reaction between ethyl magnesium bromide and cinnamyl chloride. 

More recently, Polish chemists have reported a synthesis of both aryl and aliphatic secondary nitramines by treating amine substrates with ethyl magnesium bromide followed by reaction with n-butyl nitrate (Equation 5.8). This method, which uses nonpolar solvents like hexane or benzene, has been used to synthesize aliphatic secondary nitramines, and At-nitro-A-methylanilines which otherwise undergo facile Bamberger rearrangement in the presence of acid. The direct nitration of At-unsubstituted arylamines usually requires the presence of an electron-withdrawing group. Reactions are retarded and yields are low for sterically hindered amines. 

More conclusive evidence for the intermediacy of benzocyclopropenyl cations was obtained upon chloride/fluoride exchange of 22 with AgF in acetonitrile, which led to the chloro-fluoro derivative 278 and, ultimately, to the difluoro compound 279 in almost quantitative yield. Reaction of 22 with LiAlH AlClj afforded 2,5-diphenylbenzocyclopropene (264), while that with ethyl magnesium bromide lead to the diethyl derivative 280. Phenylmagnesium bromide and methylmagne-... 

Into a 2-L three-necked flash equipped with a mechanical stirrer containing 650 mL of dry THF, purified, and dry acetylene gas was slowly introduced at room temperature for 1 h. While acetylene gas was continuously introduced, ethyl magnesium bromide (3-M solution in ether, 100 mL, 300 mmol) was added dropwise over 5 h. The reaction mixture was stirred 1 h more after the addition. A solution of 1 (23.4 g, 90.7 mmol) [Eq. (2)] in 100 mL of THF was added dropwise to the reaction mixture over 40 min, and stirring was continued for 1 h. The reaction mixture was concentrated under vacuum to about 200 mL, and then saturated aqueous NH4C1 solution was added. Organic solvent was removed under reduced pressure, and the residual aqueous mixture was extracted with ether (4 x 200 mL). The combined... 

Triethyl carbinol has been prepared by the action of zinc on a mixture of ethyl iodide and diethyl ketone 1 by the action of magnesium on ethyl bromide in diethyl ketone solution 2 as a by-product in the reaction between ethylmagnesium bromide and carbon oxysulfide 3 by the action of ethylmagnesium bromide on ethyl propionate 4 by the action of ethylmagnesium bromide on ethyl chloroformate 5 and by the action of ethyl-magnesium bromide on ethyl cyanoformate.6... 

Some other reaction courses were also seen. For example, 3a, R=octyl with butyllithium gave no significant yield of dodecane. The 31P chemical shift of an important component suggested an ylide, perhaps derived from butyltriphenylphosphonium from attack at P rather than C. Ethyl magnesium bromide with 3a, R=octyl gave mostly 1-bromooctane, but with butylmagnesium chloride, about 20% yield of dodecane was observed with no 1-chlorooctane. 

All apparatus was dried and the reaction was carried out under an inert atmosphere of argon. A solution of S-(+)-2,2-diphenyl-4-dimethylaminopentanenitrile (10.0 g, 0.018 mol) in toluene (15 ml) was added to a stirred solution of 3 M ethyl magnesium bromide in ether (10.7 ml, 0.03 mol). The ether was removed under reduced pressure and the remaining solution heated at reflux (135°-140°C) for 3 h. The solution went slightly cloudy but there was no significant precipitation. After cooling to room temperature 2 N HCI (30 ml) was added with care and then stirring was... 

To ethyl magnesium bromide (2 L, 3 M) was added over 45 min with stirring and cooling m-chlorobenzonitrile (688.0 g, 5 mole) in ether (2.5 L). The resultant solution was heated under gentle reflux for 5 h. The reaction mixture was hydrolyzed with cold dilute hydrochloric acid, the ether was distilled off, and the aqueous solution was heated at 90°C for 1 h. The flask was then cooled. The solid ketone that separated was washed with cold water and recrystallized from methanol. The recrystallized m-chloropropiophenone, melting point 39°-40°C, weighed 750.0 g. 

---