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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.
Reactions of Grignard reagents with carbonyls. The most common application of Grignard reagents is the alkylation of aldehydes and ketones, i.e. the Grignard reaction: [16] Reaction of CH 3 C(=O)CH(OCH 3) 2 with H 2 C=CHMgBr. Note that the acetal functional group (a protected carbonyl) does not react.
In acidic conditions, alkyl substituents acting as electron withdrawing groups decrease the reaction rate. [10] As bulker silyl groups are more likely to be electron withdrawing, it is easier to differentiate between less and more bulky silyl groups. [10] Therefore, acidic deprotection occurs fastest for less sterically bulky alkyl silyl groups ...
The silyl group is a non-polar and relatively unreactive species and is therefore tolerant of many reagents and reaction conditions that might be incompatible with free alcohols. Consequently, the silyl group also eliminates the need for introduction of hydroxyl protecting groups. In short, by deferring introduction of an alcohol to a late ...
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.
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 ...
The conversion is similar to the Grignard reaction. The organozinc reagent is generated via an oxidative addition into the alkyl halide. The reaction produces a primary, secondary, or tertiary alcohol via a 1,2-addition. The Barbier reaction is advantageous because it is a one-pot process: the organozinc reagent is generated in the presence of ...