Dimethyl reaction with phenylmagnesium

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. ... 

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. 

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... 

Scheme 1034. The synthesis of (l/ )-l-phenylpropylamine hydrochloride. Beginning with tert-butyl disnlfide, oxidation with hydrogen peroxide in the presence of VO(acac>2 and (5 )-2-(A -3,5-di-f-butylsaIicylidene)amino-3,3-dimethyl-l-butanol prodnces the chiral sulfinate (5 )-f-butyl-f-butanethiosulfinate. Then, addition of the sulfinate in THF (oxocyclopentane, THF) to a suspension of lithium amide (L1NH2) in Uquid ammonia (NHs )) generates K)-t-butanesulfinamide. The optically active sulfinamide reacts with propanal to form the corresponding sulfinimine. Reaction of the latter with phenylmagnesium bromide (CtllsMgBr) in ether yields A -(l-phenylpropyl)-f-butanesulhnamide and hydrolysis in methanolic HCI generates the corresponding (IR)-l-phenylpropylamine hydrochloride. The cartoon drawing of the presumed cyclic transition state is used to account for the stereochemical outcome. But see Hose, D. R. I Mahon, M. E Molloy, K. C. Raynham, T Wills, M. /. Chem. Soc. Perkin Trans. 7,1996, 7, 691.

Preparation by demethylation of 2,3-dimethyl-4-methoxy-benzophenone (SM) with pyridin-ium chloride at 180° for 2 h. SM was prepared by reaction of phenylmagnesium bromide with 2,3-dimethyl-4-methoxybenzal-dehyde in ethyl ether at 0° for 30 min [477],... 

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

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