Magnesium halides, Grignard

Aryl halides form Grignard reagents when reacted with magnesium. 

Grignard reaction. The reaction of metallic magnesium with a suitable organic halide to form an organomagnesium halide or Grignard reagent ... 

It is worth mentioning that the synthesis of allenes from propargyl halides in Grignard reactions is favored by transition metal catalysis more than by the participation of allenic carbene intermediates in as much as the level of metal impurities in magnesium turnings is not reduced to a minimum, or metal salts such as ferric chloride and other metal chelates such as nickel acetoacetonate are added to the reaction mixture. ... 

Table 21 Stability of DCPH Toward Alkyl Halide and Grignard Reagent Reaction of Bromooctane with Magnesium in the Presence of DCPH...

Alcohols react with HX to form alkyl halides, but the reaction works well only for tertiary alcohols, R,COH. Primaiy and secondary alkyl halides are normally prepared from alcohols using either SOClj or PBr ). Alkyl halides react with magnesium in ether solution to form organomagnesium halides, or Grignard ret ents (RM O- Since Grignard reagents are both nucleophilic and basic, they react with acids to yield hydrocarbons. The overall result of Grignard formation and protonation is the conversion of an alkyl halide into an alkane (RX— RM RH). 

Metal Halides and Other Salts. The more reactive organometallic types will exchange their alkyl groups for the halogen or acid anion of the salt of some less reactive metal or metalloid. Thus the reactive lithium and magnesium (Grignard) alkyls can form metal alkyls from many other metal salts. For example,... 

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