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Grignard reagents or Grignard compounds are chemical compounds with the general formula R−Mg−X, where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride Cl−Mg−CH 3 and phenylmagnesium bromide (C 6 H 5)−Mg−Br. They are a subclass of the organomagnesium compounds.
The addition of Grignard reagents to alkynes is facilitated by a catalytic amount of copper halide. Transmetalation to copper and carbocupration are followed by transmetalation of the product alkene back to magnesium. The addition is syn unless a coordinating group is nearby in the substrate, in which case the addition becomes anti and yields ...
A solution of a carbonyl compound is added to a Grignard reagent. (See gallery) An example of a Grignard reaction (R 2 or R 3 could be hydrogen). The Grignard reaction (French:) is an organometallic chemical reaction in which, according to the classical definition, carbon alkyl, allyl, vinyl, or aryl magnesium halides (Grignard reagent) are added to the carbonyl groups of either an aldehyde or ...
The first step of the Bouveault aldehyde synthesis is the formation of the Grignard reagent. Upon addition of a N , N -disubstituted formamide (such as dimethylformamide ) a hemiaminal is formed, which can easily be hydrolyzed into the desired aldehyde.
Alkylzinc reagents can be accessed from the corresponding alkyl bromides using iodine in dimethylacetamide (DMAC). [46] The catalytic I 2 serves to activate the zinc towards nucleophilic addition. Aryl zincs can be synthesized using mild reaction conditions via a Grignard like intermediate.
The reaction mechanism [8] of the Bartoli indole synthesis is illustrated below using o-nitrotoluene (1) and propenyl Grignard (2) to form 3,7-dimethylindole (13). The mechanism of the Bartoli indole synthesis. The mechanism begins by the addition of the Grignard reagent (2) onto the nitroarene (1) to form intermediate 3.
The more reactive species, a LiCl-iPrMgCl complex, is called a Turbo-Grignard reagent. These species are related to Turbo-Hauser bases, a family of magnesium amido compounds containing also LiCl. [8] "Turbo-Grignards", as they are often called, are aggregates with the formula [i-PrMgCl·LiCl] 2.
The Bodroux–Chichibabin aldehyde synthesis is a chemical reaction whereby a Grignard reagent is converted to an aldehyde one carbon longer. Reaction of a Grignard reagent with triethyl orthoformate gives an acetal, which can be hydrolyzed to an aldehyde. For example, the synthesis of n-hexanal: [1] Bodroux-Chichibabin hexanal [1]