Grignard reagents alkylmagnesium halides

Many other kinds of organometallic compounds can be prepared in a manner similar to that of Grignard reagents. For instance, alkyllithium reagents, RLi, can be prepared by the reaction of an alkyl halide with lithium metal. Alkyllithiums are both nucleophiles and strong bases, and their chemistry is similar in many respects to that of alkylmagnesium halides. 

Grignard reagents, there is an equilibrium between an alkylmagnesium halide and a dialkylmagnesium. 

Improved yields of cyclopropylamines 47 could be obtained by using methyltitanium triisopropoxide (53) instead of titanium tetraisopropoxide [108], as well as by adding the Grignard reagent to the mixture of the amide and the titanium reagent at ambient rather than low temperature (Schemes 11.15 and 11.16, and Table 11.9) [67,69]. In principle, methyltitanium triisopropoxide requires only one equivalent of the alkylmagnesium halide to generate a dialkyltitanium diisopropoxide intermediate 55, and in this particular case P-hydride elimination can only occur at the non-methyl substituent so that methane... 

In 1982, JnUa s group showed that vinyl snUones react with Grignard reagents in the presence of iron salts to afford moderate yields of conpling product (Scheme 25). The reaction is stereoselective but its scope is limited. Thus, with secondary alkylmagnesium halides, only the reduction product is formed. 

Dithioesters. These esters have been prepared by reaction of Grignard reagents with carbon disulfide in THE and then with an alkyl halide. However, yields were low with f-alkylmagnesium halides. The yields are greatly improved by addition of catalytic amounts of copper(I) bromide, and a wider range of Grignard reagents can... 

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