Ether formation bromoacetate

Bromoacetic acid has been prepared by direct bromination of acetic acid at elevated temperatures and pressures,2-3-4 or with dry hydrogen chloride as a catalyst 6 and with red phosphorus as a catalyst with the formation of bromoacetyl bromide.6-7-8-9-19 Bromoacetic acid has also been prepared from chloroacetic acid and hydrogen bromide at elevated temperatures 6 by oxidation of ethylene bromide with fuming nitric acid 7 by oxidation of an alcoholic solution of bromoacetylene by air 8 and from ethyl a,/3-dibromovinyl ether by hydrolysis.9 Acetic acid has been converted into bromoacetyl bromide by action of bromine in the presence of red phosphorus, and ethyl bromoacetate has been... 

The carbonyls Fe(CO)5 and [CpFe(CO)2]+ (2) form stable cationic complexes with alkenes, which are used for both protection and activation of alkenes [1]. [CpFe(CO)2]+ (2 abbreviated as Fp+) is prepared by the reaction of cyclopentadienyl anion (1) with Fe(CO)5, followed by oxidative cleavage with bromine, and used for the protection of alkenes. The electron density of the double bond is decreased by the coordination of [CpFe(CO)2]+ and hence this bond is activated to nucleophilic attacks. Introduction of nucleophiles, such as the carbon nucleophile of malonate, to cyclopentene becomes possible via the formation of the complex 3, and the stable tftmv-er-alkyliron complex 4 of cyclopentane is prepared. The vinyl ether complex 6 is obtained easily from the a-bromoacetal 5, and reacts with an enolate of ketone 7 as an... 

Alcohol 6 is prepared by a copper-catalyzed reaction of (R)-benzylglycidyl ether with vinylmagnesium bromide. The first step here is a Williamson ether synthesis. The free alcohol 6 reacts with sodium hydride to a sodium alkoxide, which is treated with the sodium salt of bromoacetic acid. The acid is also converted into the sodium salt to avoid the formation of an ester as side product. After the reaction carboxylic acid 20 is released in 93 % yield by acidification with aqueous 10 % HC1 solution. 

Alkylation of thiopyrrolidone with ethyl bromoacetate gives the thio-ether, which undergoes sulfur extrusion with carbon-carbon bond formation on treatment with (C6H5)3P and base. ... 

The modifications of the Gilman-Speeter reaction include the activation of zinc by tri-methylsilyl chloride (TMSCl) and the application of lithium ester enolate" or lithium thioester enolate as the substitute for the traditional Reformatsky reagent. In these modifications, it was found that TMSCl-activated zinc is much more effective in promoting the reaction between ethyl bromoacetate and Schiff bases. In addition, in the presence of a chiral ether ligand, the reaction between lithium ester enolate and imines affords 0-lactams of high enantiomeric excess, probably due to the formation of a ternary complex reagent. " The enantioselectivity and reactivity of the ternary complex depend on the size and nature of the lithium amide used. For example, the lithium amide from 2,2,6,6-tetramethylpiperidine (LTMP) is unfavorable for this reaction." ... 

Analogously, the polyisoprenoid plaunotol 164 was synthesized from allyl dimethylamine 159 tScheme 15.381. Alkylation with ethyl bromoacetate and deprotonation with KOt-Bu yielded ammonium ylide 161, which rearranged to a-aminoester 163. The exclusive formation of a single olefin isomer in 163 presumable occurs via transition state 162. Reductive removal of the dimethylamine group and benzyl ethers, along with conversion of the ester into the hydrocarbon side chain, yielded the natural product plaunotol 163. 

The chelates are prepared in anhydrous DMF or DMSO by ionization of the desired number of hydroxyl groups of the sucrose molecule with stoichiometric cunounts of sodium hydride to form alcoholates which, with metal salts, give the chelates. The etherification of sucrose with alkyl halides or esterification with organic acids caus is hydrolysis. The hydrolysis or diether formation is avoided if sucrose chelate is etherified at moderate temperatures and with only a small excess of allyl halide or sodium bromoacetate, giving 55-69% mono- and 0-2% diallyl ethers respectively, 41-48% mono- and 4-7% dicarboxymethyl ethers of sucrose. 

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