Methylmagnesium iodide, reaction with

Reaction with a-chloroacylsiianes. Methylmagnesium iodide reacts with a-chloroacyltrimethylsilanes (2), readily available from silyl enol ethers (1), to give -ketoalkyltrimethylsilanes (3). The reaction involves rearrangement of the silyl group to the adjacent carbon atom. ... 

Red phosphorus is reported not to react with methylmagnesium iodide or with diethylzinc (7). Reaction of black phosphorus as the anode in an electrolytic cell with Grignard reagents, however, is reported to yield tertiary phosphines (8). 

The 7a-methyl-7 -hydroxy compound (32) was obtained from reaction of (31) with 3 moles of methylmagnesium iodide for 16 hours at room temperature followed by 2 hours reflux. 

Oxime 26 was prepared from 5,ll-dihydro-dibenzo[a,d]cyclohepten-10-one. The Hoch-Campbell reaction of 26 with 3-dimethylaminopropylmagnesium bromide produced aziridine 27 in 46% yield after acidic workup. Extension of the Hoch-Campbell reaction to steroids has also been reported. Thus, treatment of 3(3-hydroxy-5-pregnen-20-one oxime (28) with methylmagnesium iodide furnished a mixture of diastereomers, 20ot/20P,21-imino-20-methyl-5-pregnen-3P-ol (29) in a 50% combined yield and a 3 1 ratio. On the other hand, homo-adamantan-4-one oxime (30) was transformed to homo-adamantano[4,5-b]-2 -ethylaziridine (31) in 76% yield upon the action of... 

Acetylisothiazoles have been prepared by ketonic hydrolysis of the jS-ketoesters derived from the Claisen condensation on 5-ethoxycar-bonylisothiazoles. 5-Acetyl-3-methylisothiazole is also obtained from the reaction of 5-cyano-3-methylisothiazole with methylmagnesium iodide. ... 

To a solution of 2 mols of methylmagnesium iodide in 1.5 liters of ether are added with vigorous stirring 107 g (0.5 mol) of ethyl p-chloroatrolactate. The reaction mixture is stirred for about sixteen hours, and is then decomposed by the addition of about 320 ml of saturated aqueous ammonium chloride solution. After standing, the ether layer is decanted from the mixture and the aqueous phase and the precipitated salts are washed with several 500 ml portions of ether. The combined ether solution and washings are washed with successive 500 ml portions of 5% ammonium chloride solution and water, are dried over anhydrous magnesium sulfate, and are evaporated to dryness in vacuo. The crystalline residue consisting of 2-p-chlorophenyl-3-methyl-2,3-butanediol, is recrystallized from a mixture of benzene and petroleum ether. 

Using oxathiane 11, ( + )-(i )-2-methoxy-2-phenylpropanoic acid was obtained in 97% ee, however, the synthesis contains some inconvenient reaction steps. Thus, reduction of ( + )-10-camphorsulfonic acid (8) leads in low yield to a mixture of 10-mercaptoisoborneol (9 A) and 10-mercaptoborneol (9B) which must be separated by chromatography. The oxathiane 10 resists deprotonation with butyllithium and, therefore,, y -butyllithium had to be employed. Furthermore, after addition of methylmagnesium iodide, cleavage of the oxathiane moiety 12, with iodomethane did not proceed as well as with the simpler oxathianes 3. 

The Grignard reaction of protoberberines is a well-known method for preparation of 8-alkylprotoberberines. For example, treatment of berberine with methylmagnesium iodide followed by reduction with sodium borohydride gave a 5.5 1 mixture of ( )-cis- and ( )-tr[Pg.217]

Determinations of active hydrogen with methyllithium and with methylmagnesium iodide were undertaken by Uytterhoeven and Fripiat (366). Only after outgassing at 600° or higher, did the results of both methods agree with each other and with the weight loss on calcination. The reactions proceeded more slowly than with Aerosil silica (195). Apparently, diffusion into the pores is hindered, especially with the Grignard compound. 

Apart from the reaction of cyclohexanecarboxylic acid with methyllithium, cyclohexyl methyl ketone has been prepared by the reaction of cyclohexylmagnesium halides with acetyl chloride or acetic anhydride and by the reaction of methylmagnesium iodide with cyclohexanecarboxylic acid chloride. Other preparative methods include the aluminum chloride-catalyzed acetylation of cyclohexene in the presence of cyclohexane, the oxidation of cyclohexylmethylcarbinol, " the decarboxylation and rearrangement of the glycidic ester derived from cyclohexanone and M)utyl a-chloroj)ropionate, and the catalytic hydrogenation of 1-acetylcycIohexene. "... 

The esters of the optically active alcohols with a-oxobenzeneacetic acid, 18 or ent- 18, are treated with methylmagnesium iodide to give in a diastereoselective reaction two atrolactic acid esters, one of which prevails. The mixture of esters is then hydrolyzed (of course, quantitative hydrolysis is necessary ) and the configuration of the excess atrolactic acid enantiomer (+ )-( )-23 or (-)-(R)-23 is determined by an appropriate method (optical rotation, NMR in the presence of optically active shift reagents or solvents, GLC. of diastereomeric derivatives). 

There is one other report in the literature of a measurement of the enthalpy of formation of an organomagnesium halide. The enthalpy of reaction of magnesium with methyl iodide in ether was calorimetrically determined as —273.6 0.8 kJmoH Using a recent enthalpy of formation for liquid methyl iodide of —13.6 0.5 kJmoU, the enthalpy of formation of methylmagnesium iodide is —287.2 kJmoU. The exchange (equation 8) is thus 11.2 kJmoU endothermic. 

Methanesulfonyl chloride has been prepared by the chlorination of methyl thiocyanate, S-methylthiourethan, sodium methyl thiosulfate or S-methylisothiuronium sulfate from sodium methanesulfonate by the action of phosphorus penta-chloride, phosphorus oxychloride, or benzotrichloride from methanesulfonic acid by the action of phosphorus pentachloride or by the reaction of methylmagnesium iodide with sulfuryl chloride. ... 

To a flask containing 2 moles of methylmagnesium iodide in ether is added dropwise 99 gm (1.0 mole) of iV-methyl-2-pyrrolidone dissolved in 100 ml of ether. The reaction mixture is allowed to stand overnight, then hydrolyzed with an equivalent of hydrochloric acid, the aqueous layer separated and made alkaline with sodium hydroxide. Steam distillation of the aqueous layer yields the product, which is dried over potassium hydroxide and then redistilled to afford 48.5 gm (50%) N-methyl-2-methylpyrroline, b. p. 130°-131°C. 

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