6.41E - Organic Chemistry (Mcmurry)

Question

For each alkene below, use curved arrows to show how it would react with a proton. Draw the carbocation that would form in each case.

a)

b)

c)

Step-by-Step Solution

Answer

a)

Structure of carbocation

b)

Structure of carbocation

c)

Structure of carbocation

Step 1: Carbocation

A carbocation is formed by losing two valence electrons from a carbon atom. It is an ion with a positively charged carbon atom.

In carbocation, the positively charged carbon atom is hybridized and has a trigonal planar geometry. The p-orbital is empty and bears a positive charge since it represents the orbital available to accept the electron. 

A tertiary carbocation is more stable than secondary carbocation, followed by primary carbocation.

Step 2: a) Reaction of alkene

Alkene reacts with the proton in the following way leading to the formation of a carbocation which is represented as:

                                           Formation of carbocation

                                                

The structure of carbocation is as follows:

Structure of carbocation

Step 3: b) Reaction of alkene

Alkene reacts with the proton in the following way leading to the formation of a carbocation which is represented as:

                        Formation of carbocation

 The structure of carbocation is as follows:

Structure of carbocation

Step 4: c) Reaction of alkene

Alkene reacts with the proton in the following way leading to the formation of a carbocation which is represented as:

                                   Formation of carbocation

The structure of carbocation is as follows:

                          

                                 Structure of carbocation