Aqueous-Based Organozinc Reactions

Because the organomagnesium reagent reacts with water, carbon dioxide, and oxygen, it must be protected from air and moisture when it is used. The apparatus in which the reaction is to be conducted must be scrupulously dry, and the solvent must be completely anhydrous. In addition, diethyl ether is required as a solvent without the presence of an ether, the organomagnesium reagent will not form. 

This experiment presents a variation on the basic idea of a Grignard synthesis, but one that does not use magnesium and that can be conducted in a mixed organic-aqueous solution. The reaction presented in this experiment is a variation on the Barbier-Grignard reaction, where zinc is used as the metal. A small amount of an ether, in this case tetrahydrofuran (THE), is still required for this reaction, but the principal component of the solvent system is water. By eliminating much of the organic solvent, this method can be used to illustrate some of the principles of 

Technique 25 Sections 25.2,25.4 Technique 26 Section 26.1 Technique 27 Section 27.1 

This reaction involves the use of allyl bromide, a substance that is volatile and may also be a lachiymator. Be certain to dispense this material under the hood. Do not attempt to weigh this substance determine the approximate volume of allyl bromide needed using the specific gravity provided in this experiment, and dispense the allyl bromide by volume using a calibrated pipette. Students should work in pairs for this experiment. 

All aqueous solutions should be placed in a waste container designated for the disposal of aqueous wastes. 

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Exp. 37, "Aqueous-Based Organozinc Reactions" Exp. 34, "Sonogashira Coupling of lodoaromatic Compounds with Alkynes"... 

N,N-Diethyl-m-toluamide (OEF), new procedure Diels-Alder Reaction with Anthracene-9-methanol Identification of Unknowns, revised procedure Competing Nucleophiles in S l and Sj. 2 Reactions Investigations Using 2-Pentanol and 3-Pentanol Friedel-Crafts, more substrates added Aqueous-Based Organozinc Reactions... 

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