Question

Which is/are correct statements about the major product?

(A) An endocytic Hofmann product
(B) An exocyclic Hofmann product
(C) An endocyclic Saytzeff product
(D) An exocyclic Saytzeff product

Answer 1

Hint: To solve this question, first we have to understand what is the Hofmann reaction and the Hofmann product. Next we have to look into the Saytzeff product. Also to answer the question, we have to write the complete equation of the reaction between the $ 1 - $ bromo $ 1 - $ methylcyclohexane with Potassium tert butoxide.

Complete answer:
Actually the Hofmann reaction is a type of elimination reaction of amines, where the least stable alkene i.e. the least substituted alkene is formed as a product.
According to this Hoffmann rule, the steric effects have the greatest influence on the products obtained in the Hofmann or other similar elimination reactions.
Whereas, on the other hand Saytzeff product is also known as the Zaitsev rule. According to the Saytzeff rule, the more substituted alkene is the major product.
Now, let’s solve the given above equation on the basis of our discussion about the Saytzeff and the Hofmann rule.
So, solving the equation, we will get:

So, we are very clear with the above equation.
Hence, when $ 1 - $ bromo $ 1 - $ methylcyclohexane reacts with Potassium tert butoxide , the products formed are the Methylenecyclohexane and the $ 1 - $ Methyl cyclohex $ 1 - $ ene .
Out of the two products formed, the major product is Methylenecyclohexane , which is a exocyclic Hofmann product and the minor product is $ 1 - $ Methyl cyclohex $ 1 - $ ene , which is a endocyclic Saytzeff product.
So, on the basis of our above discussion , the correct option is B. i.e. An exocyclic Hofmann product.

Note:
There is a very important difference to note between the identification of an endocyclic and the exocyclic product. So the endocyclic product is the one which has double bonds in the ring and the exocyclic compound is the one which has double bonds outside the ring.