Grignard reagent metallation with

The free dithiocarboxylic acids can be isolated, but their salts are preferred. In some cases their metal complexes can be prepared directly by insertion of carbon disulfide into metal-carbon bonds. Thus, the reaction of Grignard reagents, RMgX, with CS2, followed by acid treatment gives the dithiocarboxylic acids RCSSH and metal complexes in good yields.311... 

Among the more exotic cydopropylallenes, the polycyclic hydrocarbons 148 (n= 2, 3) may be cited, which are available by coupling the Grignard reagents 147 with propargyl bromide (116) in the presence of various metal catalysts, Fe(acac)3 leading to the highest yields (Scheme 5.21) [60]. 

Grignard reagents react with halides of less electropositive metals to give other organometallic compounds. The less electropositive (more electronegative) metals include Hg, Zn, Cd, Si, and the nonmetal P. An example of this type of reaction is... 

Grignard reagents add with difficulty to imines derived from enolizable carbonyl compounds. The activation of the C=N bond can be achieved either by attachment of an electron-with drawing group or A-coordination with a Lewis acid . The use of a catalytic amount of the soluble rare-earth metal complex LnCl3 2LiCl allows the addition of... 

The reaction of the Grignard reagent CgHgMgBr with metal salts Droved to be the most widely applicable method. Depending on the re-... 

This chapter will focus on the nucleophilic addition reactions of transition metal vinylidenes and allyl complexes with Grignard reagents. Reactions with transition metal vinylidenes will be discussed initially, and then a brief review of allyl complexes with Grignard reagents will conclude the chapter. The synthesis and some general reactions of these vinylidene and allyl complexes will be presented. A more detailed description of the chemistry of these metal complexes can be found in the literature [1]. 

The preparation of a Grignard reagent begins with magnesium metal and dry ether (in most cases, either diethyl ether or THF, tetrahydrofuran). The ether cleans the surface of the metal and takes the reagent into solution for reaction. (If either the ether or the reaction vessel contains moisture, the yield is poor.) The magnesium then reacts with either an alkyl halide or an aryl halide. The ease of reactivity decreases in the order RI > RBr > RC1. Iodides may react too rapidly, but chlorides may react too slowly. Thus bromides are usually the best. The general reaction is... 

Phosphine-nickel and -palladium complexes have been used as catalysts for the reaction of Grignard reagents (RMgX) with vinyl or aryl halides (R X ) to produce, selectively, cross-coupling products (R-R ). The catalytic cycle of the reaction has been proposed to consist of a sequence of steps involving a diorgano-metal complex (LnM(R)R ) as a key intermediate (Scheme I). 

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