Butyl bromide Grignard reaction with

By reaction of 3-thienyllithium with magnesium bromide, the Grignard reagent, free from entrainment Grignard reagent, was obtained,- which is useful for the preparation of 3-acetothiophene by reaction with acetic anhydride at —70 0 and for the preparation of 3-t-butoxythiophene through reaction with t-butyl perbenzoate. It is the opinion of the present author that most 3-substituted thiophenes are prepared more conveniently from 3-thienyllithium than from 3-thenyl bromide. The latter method, however, is superior if the introduction of the 3-thenyl group is desired. 

Polarization also occurs in coupling and disproportionation reactions of Grignard reagents with alkyl halides. The vinyl protons of isobutene produced in the reaction of t-butylmagnesium chloride with t-butyl bromide show A/E polarization as do the methyl protons of isobutane (Ward et al., 1970). Similar results arise in the reaction of diethyl-magnesium with organic halides (Kasukhin et al., 1972). 

One of the important new directions in the study of addition reactions of organozinc compounds to aldehydes is the use of ionic liquids. Usually, application of these compounds in reactions with common organometallic reagents has a serious problem ionic solvents are usually reactive toward them, particularly Grignard and organolithium derivatives. It has been recently reported that carbonyl compounds react with allylzinc bromide formed in situ from allyl bromide and zinc in the ionic liquid 3-butyl-l-methylimidazolium tetrafluoroborate, [bmim][BF4].285 Another important finding is that the more reactive ZnEt2 alkylates aldehydes in a number of ionic liquids at room temperature.286 The best yields (up to 96%) were obtained in A-butylpyridinium tetrafluoroborate, [bpy][BF4] (Scheme 107). 

Glyoxal-sodium bisulfite, 30, 86 Glyoxylic acid, w-butyl ester, 35, 18 ethyl ester, diethyl acetal, 35, 59 Grignard reaction, addition to ethyl sec-butylidenecyanoacetate, 35, 7 allylmagnesium bromide with of,(3-di-bromoethyl ethyl ether, 36, 61 allylmagnesium chloride with a,/3-di-bromoethyl ethyl ether, 36, 63 ethylmagnesium bromide with tin tetrachloride, 36, 86... 

Penfluridol Penfluridol, 4-(4-chloro-3-trifluoromethylphenyl)-l-[4,4-Z M-(p-fluorophenyl) butyl]-4-piperidinol (6.6.12), is synthesized implementing a Grignard reaction between l-carbomethoxypiperidin-4-one and 4-chloro-3-trifluoromethylphenylmagnesium bromide, giving l-carbomethoxy-(4-chloro-3-trifluoromethylphenyl)-4-piperidinol (6.6.10). Upon alkaline hydrolysis of the carbomethoxy group, it turns into (4-chloro-3-trifluo-romethylphenyl)-4-piperidinol (6.6.11), the alkylation of which with l,l-( ti(4-fluo-rophenyl)butyl bromide (6.6.3) gives penfluridol (6.6.12) [67-69],... 

Radical addition/cross-coupling products 61 were obtained in 60-91% yield when Ni(dppf)Cl2 was applied as a catalyst in reactions of alkyl halides 60 with 2,3-disubstituted dienes 59 and aryl Grignard or arylzinc reagents (Fig. 12). Competition experiments of n-, sec-, and ferf-butyl bromide with 2,3-dimethylbutadiene... 

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