Organomagnesium reagents, reaction with

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. 

The actual mechanism by which a particular reaction proceeds strongly depends on the nature of the organomagnesium reagent. For instance benzophenone reacts with methylmagnesium bromide by a polar mechanism, while the reaction with t-butylmagnesium chloride proceeds for steric reasons by a SET-mechanism. 

The reaction with organolithium or organomagnesium reagents 9 leads to formation of /3-aminoalcohols 10 ... 

The reduction of carbonyl compounds by reaction with hydride reagents (H -) and the Grignard addition by reaction with organomagnesium halides (R - +MgBr) are examples of nucleophilic carbonyl addition reactions. What analogous product do you think might result from reaction of cyanide ion with a ketone ... 

As with organomagnesium reagents, there is usually loss of stereochemical integrity at the site of reaction during the preparation of alkyllithium compounds.25 Alkenyllithium reagents can usually be prepared with retention of configuration of the double bond.26,27... 

The preparation of ketones proceeds conveniently by reaction of imidazolides with organomagnesium reagents, as shown in Table 14-6 for several examples of purely aromatic, aromatic-aliphatic, and purely aliphatic ketones. The yields are very satisfactory even for purely aliphatic ketones, since in this case, too, alcohol formation is completely suppressed.t851,t861... 

Methyl 2,3-epoxypropanoate can be prepared by reaction of potassium glycidate with dimethyl sulfate and one equivalent of benzyltriethylammonium chloride in methylene chloride at room temperature (65% yield).14 The reactions of this ester with organolithium or organomagnesium reagents at low temperature afford optically pure epoxy ketones14 that may be transformed via reductive amination to anti amino epoxides.15... 

Manganese-copper-catalyzed conjugate addition of organomagnesium reagents to a,p-enones is a general synthetic method. Table I shows that the reaction can be successfully performed even with enones of low reactivity. 30% Manganese chloride is necessary to obtain good yields. In most cases, however, 0.1% cuprous chloride is sufficient.3... 

---