Grignard compounds magnesium

Benzyl chloride readily forms a Grignard compound by reaction with magnesium in ether with the concomitant formation of substantial coupling product, 1,2-diphenylethane [103-29-7]. Benzyl chloride is oxidized first to benzaldehyde [100-52-7] and then to benzoic acid. Nitric acid oxidizes directly to benzoic acid [65-85-0]. Reaction with ethylene oxide produces the benzyl chlorohydrin ether, CgH CH20CH2CH2Cl (18). Benzylphosphonic acid [10542-07-1] is formed from the reaction of benzyl chloride and triethyl phosphite followed by hydrolysis (19). 

A modern variant is the intramolecular magnesium-ene reaction, e.g. the reaction of the alkene-allylic-Grignard compound 9 to give the five-membered ring product 10. This reaction proceeds regio- and stereoselectively, and is a key step in a synthesis of the sesquiterpenoid 6-protoilludene ... 

Addition of organometallic reagents to nitro compounds is possible but is sparingly used. Reaction of aromatic nitro compounds with large excess of phenyl magnesium bromide produces hydroxylamines in moderate yield . Similar addition of Grignard compounds to nitromethane proceeds in low yield ° while addition of excess methyllithium to tertiary nitro compound 113 results in formation of hydroxylamine 114 (equation 83) . ... 

So far, the two other Grignard compounds known as having a monomeric structure in the solid state with four-coordinate magnesium are (Ph3C)MgBr(OEt2)2 (154) ... 

The photochemistry of true organomagnesium compounds remains almost completely unexplored. A literature search in preparation of this work found only a few scattered examples of photochemical studies, mostly in relation to Grignard reactions and 1,3-diketonate chelates Similar to the situation with organozinc compounds magnesium tetrapyrrole chelates, i.e. magnesium porphyrins 1, 5,10,15,20-tetraazaporphyrins (por-phyrazines) 2 and phthalocyanines 3 have found more interest. This is primarily related... 

Functionalized aryl Grignard compounds, prepared by iodine-magnesium exchange according to the procedure reported by Cahiez, Knochel and coworkers in 1998, can be efficiently acylated. It is thus possible to prepare various polyfunctionalized diaryl ketones (Scheme 14). ... 

These observations have been interpreted in terms of the hard-soft acid-base theory (77CJC4112), in which the salts of the harder cations, such as the Li+ ion, lead to C-alkylation, whilst the salts of the soft cations, such as the quaternary ammonium salts, are TV-alkylated. This interpretation is particularly relevant in understanding the reactivity of the heteroaryl-magnesium salts. The Mg2+ ion is a harder cation than the Li+ ion and, with the more strongly associated Grignard compounds, C-alkylation predominates. Generally, the pyrrole... 

Eliminations with magnesium or phenylmagnesium bromide proceed via Grignard compounds, c.g. formation of 4 (see also Table 9).190... 

Reaction IX. (c) Action of Dimethyl Sulphate on Magnesium Alkyl or Aryl Halide (Grignard).—When a Grignard compound is treated with dimethyl sulphate, methylation of the alkyl or aryl group takes place, the metal-halogen residue being split off. (B., 36,2116. See also O.S., XI., 66.)... 

Dihydrobenzo[6]thiophene-l, 1-dioxide is metallated by ethyl-magnesium bromide in the 2-position to give the Grignard compound (355). Its 2-methyl,740-742 2-bromo,718or 2-ethoxycarbonyl215 derivative may be prepared by treating 355 with methyl iodide, bromine, or ethyl chloroformate, respectively. 2-(Ethoxycarbonyl)thioindoxyl-1,1-dioxide may be methylated in the 2-position by successive treatment with sodium ethoxide and methyl iodide.215... 

Silyl Grignard compounds can be obtained from highly reactive magnesium (given as Mg ) and halosilanes (equation 6). 

Magnesium. Reaction to give Grignard compounds may be violent.2... 

The Grignard compounds do not react directly with the starting materials, and the results can only be explained by the formation of a silyl magnesium compound during the reaction. 

Fig. 6.46. Acylation of Grignard compounds with magnesium carboxylates usually impossible (with magnesium carboxylate A), but feasible with sterically favored magnesium formate (B) or electronically favored magnesium(tri-fluoracetate) (C). These reactions allow the construction of aldehydes and trifluoro-methylketones, respectively.

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