Question

a. What product(s) are expected in the ethoxide-promoted ß-elimination reaction of 1-chloro-1-methylcyclohexane? Omit ions, salts, and ethanol from yourresponse.

b. What product(s) are expected in the ethoxide-promoted ß-elimination reaction of 2-bromo-2,3-dimethylbutane? Omit ions, salts, and ethanol from your response.

Answer 1

a)

b) CH3-C(Br)(CH3)-CH(CH3)-CH3----------------> CH3-C(CH3)=C(CH3)-CH3 (2,3 DI METHYLE BUTEEN-2)

Answer 2

You have two B-carbons, each carbon next to the bromo leaving group is a Beta i'm fairly sure.. simulate the ethoxide using its e- to take a H+ from eachof the Beta groups you have to different molecules because of the placement of the double bond.. *Repppp Dr. MASHH

Answer 3

General guidance

Concepts and reason

The product of the $\\beta$ elimination reaction of 1-chloro-1-methylcyclohexane needs to be given. The base used is ethoxide ion. Draw the structure and abstract the hydrogen that gives more substituted as well as less substituted product to get the two products.

Fundamentals

E2 reaction: It stands for elimination reaction following second order kinetics. In E2 reaction, the base abstracts the [\beta ] hydrogen and removal of the leaving group simultaneously in the same step. A general mechanism is shown below:

CH2BH+X X is the leaving group B is the base

Step-by-step

Step 1 of 3

The [\beta ] hydrogens in 1-chloro-1-methylcyclohexane are as follows:

CI H 1-chloro-1-methylcyclohexane

Explanation

Firstly, draw the parent chain cyclohexane. It is a closed structure consisting of six carbons. At the first position, attach a chlorine and a methyl group to get 1-chloro-1-methylcyclohexane.

The $\\beta$ hydrogens are seen with respect to the carbon with which the halogen that is chlorine is attached as shown in the figure.

Step 2 of 3

The major product is as follows:

CI 3%--O : Major

Explanation

The formation of major product follows Saytzeff rule. According to Saytzeff\u2019s rule, the major alkene that is formed in an elimination reaction is the one which is more substituted. The more substituted alkene is one which is attached to more number of alkyl groups. It is formed by the removal of hydrogen from the $\\beta$ carbon having lesser hydrogens.

Step 3 of 3

The minor product is as follows:

CI H C,H Minor

The products of the reaction are as follows:

CI 1-chloro-1-methylcyclohexane

Explanation

The minor product is the product that is less substituted. It is formed as per Hoffman\u2019s elimination rule. The alkene is formed by removal of hydrogen from the $\\beta$ carbon having more hydrogen.

Answer

The products of the reaction are as follows:

CI 1-chloro-1-methylcyclohexane

Answer only

The products of the reaction are as follows:

CI 1-chloro-1-methylcyclohexane