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This type of reaction is also called a 1,2-nucleophilic addition. The stereochemistry of this type of nucleophilic attack is not an issue, when both alkyl substituents are dissimilar and there are not any other controlling issues such as chelation with a Lewis acid, the reaction product is a racemate. Addition reactions of this type are numerous.
While nucleophilic acyl substitution reactions can be base-catalyzed, the reaction will not occur if the leaving group is a stronger base than the nucleophile (i.e. the leaving group must have a higher pK a than the nucleophile). Unlike acid-catalyzed processes, both the nucleophile and the leaving group exist as anions under basic conditions.
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. With added salt the main product is 1,4-adduct A (82%) with some C (7%). A 1,6-addition is also possible, for example in one step of the commercial-scale production of fulvestrant: [12]
Carboxypeptidases act by replacing the substrate water with a carbonyl (C=O) group. The carboxypeptidase A hydrolysis reaction has two mechanistic hypotheses, via a nucleophilic water and via an anhydride. In the first proposed mechanism, a promoted-water pathway is favoured as Glu270 deprotonates the nucleophilic water.
In organic chemistry, an active ester is an ester functional group that is highly susceptible toward nucleophilic attack. Activation can be imparted by modifications of the acyl or the alkoxy components of a normal ester, say ethyl acetate. Typical modifications call for electronegative substituents.
The mechanism of the Michaelis–Arbuzov reaction. The Michaelis–Arbuzov reaction is initiated with the S N 2 attack of the nucleophilic phosphorus species (1 - A phosphite) with the electrophilic alkyl halide (2) to give a phosphonium salt as an intermediate (3).
Nucleophilic conjugate addition is a type of organic reaction. Ordinary nucleophilic additions or 1,2-nucleophilic additions deal mostly with additions to carbonyl compounds. Simple alkene compounds do not show 1,2 reactivity due to lack of polarity , unless the alkene is activated with special substituents .
In the case of enone substrates, where two sites of nucleophilic addition are possible (1,2 addition to the carbonyl carbon or 1,4 conjugate addition to the β carbon), most highly reactive organolithium species favor the 1,2 addition, however, there are several ways to propel organolithium reagents to undergo conjugate addition. First, since ...