Phenylmagnesium bromide 2.6- dimethyl

What product would you expect to obtain from Grignard reaction of an excess of phenylmagnesium bromide with dimethyl carbonate, CH30C02CH3 ... 

The (R)-(+)-chiral 1,4-diol 17b was easily prepared from L-(+)-dimethyl tartrate. Dimethyl tartrate was converted to the corresponding phenylethylidene derivative by treatment with 1,1-dimethoxy-l-phenylethane and cat. p-toluenesulfonic acid in refluxing benzene, followed by conversion to the diol 17b with excess phenylmagnesium bromide. The diol was purified by column chromatography on silica gel (hexane ethyl acetate =5 1), and recrystalization from a mixture of hexane and 2-propanol. 

Theuseof DMPU (l,3-dimethyl-3,4,5,6-tetrahydro-2(l//)-pyrimidmone) as acosolvent in THF has been reported to increase the amination yield of arylzinc chlorides with Erdik and Omiir also reported competitive kinetic studies for the amination of substituted phenylmagnesium bromides and CuCN-catalyzed phenylzinc chlorides with acetone 0-(mesitylenesulfonyl)oxime 6f in THF and analyzed the rate data via the Hammett... 

A-Benzyl-2-methylaziridine with phenol and dimethylformamide at 60° formed (2S,55)-dimethyM,4-dibenzylpiperazine (1666), 1-cyclohexylaziridine with phenylmagnesium bromide gave 1,4-dicyclohexylpiperazine (1667), and some 1-alkylaziridines with alkyl, alkenyl, or benzyl halides, as well as with dialkylchloro-ethylamines, have been found to give nearly quantitative yields of the corresponding 1,1,4-trialkylpiperazinium halides (1668). Dimerization of dimethyl l-(p-methoxyphenyl)aziridine-2,3-dicarboxylate gave two isomers of 2,3,5,6-... 

Another side reaction, caused by changes in the solvent composition, was studied in 1980 (in the former USSR) and, unfortunately, was also published in rather inaccessible journals [37]. The reactions of phenylmagnesium bromide with the aliphatic ketones, 2-butanone and 3,3-dimethyl-2-butanone (methyl-fcrt-butyl ketone), were studied. Besides the carbonyl addition reaction, leading to a tertiary alcohol, enolization also takes place with this type of ketones. The enolate, on hydrolysis, yields the starting ketone however, before hydrolysis, in the reaction mixture of the Grignard reagent and the ketone, the enolate can react further with the ketone to form a condensation product (Scheme 16). 

The rates /Cenoi/ add " re 7 and 8, respectively, for the reactions of phenylmagnesium bromide with 2-butanone and 3,3-dimethyl-2-butanone, but on the addition of large amounts of triethylamine (150 and 90%, respectively, for the two reactions) these rates were almost doubled from 7 to 16 and from 8 to 14. The general conclusion from this work was that triethylamine did not change the rate of the addition reaction, but doubled the rate of the enolization reaction. Still, the influence of the amine on the rates of reactions were much smaller than for the reactions with 1-hexyne, as listed in Table 7. 

Lactones have been converted to (hydroxyalkyljcyclopropyl phenyl ketones on reaction with phenylmagnesium bromide and phenyllithium. Reductive dimerization of ethyl cyclo-propanecarboxylate with sodium gave l,2-dicyclopropylethane-l,2-dione in 69% yield when thionyl chloride treatment was carried out prior to hydrolytic workup, and to dicyclopropyl ketone in 74% yield, when workup included sodium bromate treatment. A related reaction occurred during thermolysis of 6,6-dimethyl-5,7-dioxaspiro[2.5]octane-4,8-dione to give dispiro[2.1.2.1. ]octane-4,8-dione. ... 

To a stirred suspension of l-(methylsulfanyl)-2,3-diphenyJcyclopropenylium bromide (0.95 g, 3.0 mmol) in benzene (20 mL) was added a solution of phenylmagnesium bromide (9 mmol) in EtjO (15 mL) over 5 min, and the mixture was stirred for an additional 5 min. Then crushed ice (30 g) was added portionwise and the organic layer was separated and dried (NujCOj). H NMR analysis of the product mixture, using dimethyl sulfone as an internal standard, indicated that the yield of 63 and 64 (R = R = Ph) was 64 and 23%, respectively. Column chromatography of the mixture (silica gel) afforded the major product as an oil, which was rather unstable at rt gradually rearranging to l-(methylsulfanyl)-2,3-diphenylindene mp 158 C. 

The bromo-magnesium salt of an intermediate of this type has been obtained recently by means of phenylmagnesium bromide from DL-threo-3,4-dimethyl-5-phenyl-2-oxa-zolidone G. Fodor, Chimia (Swilz.) 9, 179 (1954) K. Koezka and G. Fodor, Acta Chim. Acad. Sci. Hung. 13, 83 (1957). 

Dimethyl(phenyl)phosphine sulfide 418 Dimethylthiophosphinic bromide (16.4 g, 95 mmoles) in ether (75 ml) is added during 15 min, with stirring at 0-10°, to a solution of phenylmagnesium bromide (0.1 mole) in ether (110 ml). The mixture is set aside overnight and then poured into a mixture of ice and 10 % sulfuric acid. The aqueous layer is washed with ether, and the ethereal washings and the original ether layer are washed with water, dried over sodium sulfate, and evaporated. The residual oil crystallizes when cooled and rubbed, and on recrystallization from hexane-benzene gives the sulfide as colorless needles (14.2 g, 88 %), m.p. 47-47.7°. 

When 4 is treated with excess phenylmagnesium bromide, good to excellent yields of trans-4,5-bis(hydroxydiphenylmethyl)-2,2-dimethyl-l,3-dioxacyclopentane (21) are produced. This has been used as an effective optical resolution agent for bicyclic enones [16], and for the preparation of the hydroxythiol 22, which was transformed into the 1,3-oxathiepane 23 [17] (Scheme 5). 

Chiral auxiliaries are particularly important in asymmetric synthesis. A bicyclic orthoester derived from dimethyl-L-tartrate (la) provides a novel auxiliary with useful applications. Treating la with phenylmagnesium bromide followed by reaction with methyl 2-methoxy-2,2-dichloroacetate (commercially available) affords in greater than 75% yield the methyl... 

A vast array of arylmagnesium bromides have been successfully employed for the synthesis of m-terphenyls by this route [6a], In the present context of cuppedophane and cappedophane synthesis, the discussion can be limited to the use of a few arylmagnesium bromides (Scheme 2). The use of 2,6-dimethyl-phenylmagnesium bromide 21 followed by aqueous quench gave the m-terphenyl unit 7 in 70% yield [9]. The synthesis of 7 can easily be carried out on a 20 g scale. Electrophilic quench prior to aqueous work-up allows one to directly functionalize the internal position of the m-terphenyl. Detailed discussion of direct or indirect internal functionalization of m-terphenyl templates is given in Sect. 3.2.1. 

A soln. of methyl 2-dimethylamino-3,3-dimethylcyclobutanecarboxylate in abs. ether added dropwise to 2.4 moles ethereal phenylmagnesium bromide at such a rate as to maintain gentle reflux, after the addition refluxed 2 hrs. 1,5-diphenyl-4,4-dimethyl-5-dimethylaminopentan-l-one. Y 82%. F. e. s. L. Wein-traub et al., Am. Soc. 86, 4880 (1964) J. Med. Ghem. 9, 187 (1966). 

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