Organometallic compounds Grignard reagents

You have already had considerable experience with carbanionic compounds and their applications in synthetic organic chemistry The first was acetyhde ion m Chapter 9 followed m Chapter 14 by organometallic compounds—Grignard reagents for example—that act as sources of negatively polarized carbon In Chapter 18 you learned that enolate ions—reactive intermediates generated from aldehydes and ketones—are nucleophilic and that this property can be used to advantage as a method for carbon-carbon bond formation... 

Via organometallic compounds (Grignard reagent). Alkyl halides react with either Mg or Li in dry... 

Two other acid derivatives may also be converted to ketones by reaction with organometallic compounds. Grignard reagents add to nitriles to give imine salts (Section 14.4.3), which are hydrolyzed to ketones in the reaction work-up. In Figure 19.27, again the disconnected bond is highlighted in red. Remember than many aliphatic nitriles are readily prepared by displacement... 

Thiols and sulfides are occasionally prepared by treatment of Grignard reagents with sulfur." " Analogous reactions are known for selenium and tellurium compounds. Grignard reagents and other organometallic... 

Coupling reactions between C(5p )-organometallics, mostly Grignard reagents, and C(sp ) halides and related compounds are usually achieved with Cu catalysts. Primary alkyl halides react smoothly, secondary alkyls are applicable in only a few cases, and no successful coupling has been reported for tertiary alkyl halides. Allylic halides and related compounds are treated separately, since there are important regiochemical problems. 

Organopalladium compounds are prepared with organometallic compounds such as organoalkali metal compounds, Grignard reagents and organoaluminium compounds. For example, reactions are shown in eqs. (20.14)-(20.17) [32-35]. 

Organomagnesium compounds (Grignard reagents) and organolithium compounds are the most common organometallic compounds. They caimot be prepared from or react with compounds that contain acidic groups. 

Grignard reagents react with ethylene oxide to yield primary alcohols containing two more carbon atoms than the alkyl halide from which the organometallic compound was prepared... 

Azolium rings react readily with organometallic compounds. With a Grignard reagent, conversion (193) -> (194) is known in the benzothiazolium series, and 1,3-benzodithioly-liums give products of type (195). 

The fluorination of organometallics with Al-fluoroamide reagents has received Only limited attention. Grignard reagents, both aliphatic and aromatic, are converted to organofluonne compounds. Both the electron transfer and the Sf,j2 ntechamsms have been considered in these processes [SO, 81, 82], The reactions 0 exemplified in equation 46 [48, 69, 70, 71, 75] Organosilanes are also fluonnated [71] (equation 47)... 

Some structural aspects of the organometallic compounds of the alkali metals have already been briefly mentioned in Section 4.3.6. The diagonal relation of Li with Mg (p. 76), coupled with the known synthetic utility of Grignard reagents (pp. 132-5), suggests that Li, and perhaps the other alkali metals, might afford synthetically... 

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