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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 ...
Phenylsilane is produced in two steps from Si(OEt) 4.In the first step, phenylmagnesium bromide is added to form Ph−Si(OEt) 3 via a Grignard reaction.Reduction of the resulting Ph−Si(OEt) 3 product with LiAlH 4 affords phenylsilane.
Usually Grignard reagents are written as R-Mg-X, but in fact the magnesium(II) centre is tetrahedral when dissolved in Lewis basic solvents, as shown here for the bis-adduct of methylmagnesium chloride and THF. Grignard reagents or Grignard compounds are chemical compounds with the general formula R−Mg−X, where X is a halogen and R is an ...
Less frequently silanols are prepared by oxidation of silyl hydrides, a reaction that uses a metal catalyst: 2 R 3 SiH + O 2 → 2 R 3 SiOH. Many silanols have been isolated including (CH 3) 3 SiOH and (C 6 H 5) 3 SiOH. They are about 500x more acidic than the corresponding alcohols. Siloxides are the deprotonated derivatives of silanols: [22 ...
Trimethylsilylacetylene is commercially available. It may also be prepared in a manner similar to other silyl compounds: deprotonation of acetylene with a Grignard reagent, followed by reaction with trimethylsilyl chloride. [4] Trimethylsilylacetylene is a precursor to 1,4-bis(trimethylsilyl)buta-1,3-diyne, a protected form of 1,3-butadiyne. [5]
The products after silylation, namely silyl ethers and silyl amines, are resilient toward basic conditions. [2] Protection is typically done by reacting the functional group with a silyl halide by an SN2 reaction mechanism, typically in the presence of base. [3] The protection mechanism begins with the base deprotonating the alcohol group.
In the original paper describing this reaction, methylmagnesium bromide is reacted with isophorone with and without 1 mole percent of added copper(I) chloride (see figure). [10] Without added salt the main products are alcohol B (42%) from nucleophilic addition to the carbonyl group and diene C (48%) as its dehydration reaction product.
The major advantage of this method over addition of organometallic reagents to more typical acyl compounds is that it avoids the common problem of over-addition. For these latter reactions, two equivalents of the incoming group add to form an alcohol rather than a ketone or aldehyde. This occurs even if the equivalents of nucleophile are ...