Lithium organometallic compounds reactions

Unless otherwise known, the toxicides of lithium organometallic compounds should be regarded as those of lithium compounds and of organometallic compounds in general. The latter were discussed in Section 12.4. Lithium oxide and hydroxide are caustic bases, and they may be formed by the combustion of lithium organometallic compounds or by their reaction with water. 

The most general synthetic route to ketones uses the reaction of carboxylic acids (or their derivatives) or nitriles with organometallic compounds (M.J. Jorgenson, 1970). Lithium car-boxylates react with organolithium compounds to give stable gem-diolates, which are decom-... 

From a synthetic point of view, direct alkylation of lithium and magnesium organometallic compounds has largely been supplanted by transition-metal-catalyzed processes. We will discuss these reactions in Chapter 8 of Part B. 

Benzyne can also be generated from o-dihaloaromatics. Reaction of lithium amalgam or magnesium results in formation of a transient organometallic compound that decomposes with elimination of lithium halide. l-Bromo-2-fluorobenzene is the usual starting material in this procedure. 

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. 

E. Reacticms Involving Organometallic Compounds 1. Reaction of lithium alkyls with organic halides... 

The first example of chemically induced multiplet polarization was observed on treatment of a solution of n-butyl bromide and n-butyl lithium in hexane with a little ether to initiate reaction by depolymerizing the organometallic compound (Ward and Lawler, 1967). Polarization (E/A) of the protons on carbon atoms 1 and 2 in the 1-butene produced was observed and taken as evidence of the correctness of an earlier suggestion (Bryce-Smith, 1956) that radical intermediates are involved in this elimination. Similar observations were made in the reaction of t-butyl lithium with n-butyl bromide when both 1-butene and isobutene were found to be polarized. The observations were particularly significant because multiplet polarization could not be explained by the electron-nuclear cross-relaxation theory of CIDNP then being advanced to explain net polarization (Lawler, 1967 Bargon and Fischer, 1967). 

Studies of the effects of low frequency ultrasonic waves on a broad range of synthetically useful reactions are summarized. Discussion is centered on the results obtained in our laboratory where we have concentrated on the reactions of metals with functionalized organic and organometallic compounds. Special emphasis is on lithium and zinc with organic and organosilicon halides. 

Organometallic compounds vary widely in their properties and reactivity, just as do the elements from which they are produced. These compounds may be lithium alkyls, Grignard reagents, or organotin compounds. Accordingly, there is no universal method for preparing the compounds, but we will present here some of the types of reactions that have been widely employed. 

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