Weak nucleophiles (H-Nu) react with aldehydes and ketones under acid-catalyzed conditions. Let HA represent an acid catalyst which will react at the nucleophilic site of R₂C=O in an initial step, followed by reaction of the nucleophile (H-Nu) at the electrophilic site of R₂C=O. The final step is deprotonation the attached Nu by the conjugate base of HA. Write this mechanism. Note: all steps in your mechanism may be reversible - use equilibrium arrows. of
Reactive Intermediates
In chemistry, reactive intermediates are termed as short-lived, highly reactive atoms with high energy. They rapidly transform into stable particles during a chemical reaction. In specific cases, by means of matrix isolation and at low-temperature reactive intermediates can be isolated.
Hydride Shift
A hydride shift is a rearrangement of a hydrogen atom in a carbocation that occurs to make the molecule more stable. In organic chemistry, rearrangement of the carbocation is very easily seen. This rearrangement can be because of the movement of a carbocation to attain stability in the compound. Such structural reorganization movement is called a shift within molecules. After the shifting of carbocation over the different carbon then they form structural isomers of the previous existing molecule.
Vinylic Carbocation
A carbocation where the positive charge is on the alkene carbon is known as the vinyl carbocation or vinyl cation. The empirical formula for vinyl cation is C2H3+. In the vinyl carbocation, the positive charge is on the carbon atom with the double bond therefore it is sp hybridized. It is known to be a part of various reactions, for example, electrophilic addition of alkynes and solvolysis as well. It plays the role of a reactive intermediate in these reactions.
Cycloheptatrienyl Cation
It is an aromatic carbocation having a general formula, [C7 H7]+. It is also known as the aromatic tropylium ion. Its name is derived from the molecule tropine, which is a seven membered carbon atom ring. Cycloheptatriene or tropylidene was first synthesized from tropine.
Stability of Vinyl Carbocation
Carbocations are positively charged carbon atoms. It is also known as a carbonium ion.
Below are the 3 steps of the complete mechanism:
Step-1: Reaction of HA to the nucleophilic site of R2C=O.
Step-2: Reaction of Nucleophile(H-Nu) at the electrophilic site of R2C=O.
Step-3: deprotonation of the attached Nucleophile(H-Nu+-) by the conjugate base of HA, A-.
All the steps are shown below:
Step by step
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