Allylic Vs Vinylic Carbocation

Do not confuse an allylic group with a vinyl group.

Allylic vs vinylic carbocation.

In the tertiary carbocation shown above the three alkyl groups help to stabilize the positive charge. An allylic carbocation is a resonance stabilized carbocation in each of the two resonance forms of which the formal charge of 1 is on an allylic carbon. As expected from its sp hybridization the vinyl cation prefers a linear geometry. What is vinylic carbon.

It is sp 2 hybridized. N1 reactions of allylic halides allylic halides and sulfonates are more reactive toward than simple alkyl halides toward nucleophilic substitution by the s n1 mechanism cc hc h h ch 3 ch 3 cc hc h h cl ch 3 ch 3 h h cc hc h h oh ch 3 ch 3 cc cch 3 ch 3 h oh h h cc cch 3 ch 3 h cl h h resonance stabilized carbocation intermediate over 100x. Vinylic carbocations are unstable as they lack p character. Vinylic carbon makes a double bond with another carbon which is also sp 2 hybridized.

An allylic system has a minimum of 3 carbons. Atoms or groups attached to an allylic carbon are termed allylic substituents. An allylic carbocation in which an allylic carbon bears the positive charge. For example s n 1 reaction.

Due to the stability of the carbocation allyl compounds radially form intermediates during the reaction. An allylic carbon is one that is directly attached to a pi bond. Vinylic carbon is a carbon that is involved in a double bond with another carbon. The double bonded carbon atoms can be classified as vinylic and allylic carbon atoms.

Allyl group gets attached to any other group of atoms through ch 2 group. That is the charge has been dispersed. Allyl form a stable carbocation because of the electron delocalization. Both carbons involved in this bond are vinylic carbons.

A vinyl carbocation has a positive charge on the same carbon as the double bond.