2,2-Dimethylcyclohexanol is heated with concentrated H3PO4. The major alkene and the key step leading to it are

1,2-dimethylcyclohexene, formed after a 1,2-methyl shift

1,2-dimethylcyclohexene, formed by direct loss of H from C-2

1,2-dimethylcyclohexene, formed after a 1,2-methyl shift

1,6-dimethylcyclohexene, formed after a 1,2-methyl shift

3,3-dimethylcyclohexene, formed directly without a shift

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JEE Advanced levelSingle correct optionDifficulty 3 of 3o4012

2,2-Dimethylcyclohexanol is heated with concentrated $H X_{3} PO X_{4}$ . The major alkene and the key step leading to it are

A1,2-dimethylcyclohexene, formed by direct loss of H from C-2
B1,2-dimethylcyclohexene, formed after a 1,2-methyl shift
C1,6-dimethylcyclohexene, formed after a 1,2-methyl shift
D3,3-dimethylcyclohexene, formed directly without a shift

Answer: B

Ionisation gives the secondary cation at C-1, next to the quaternary C-2, which has no hydrogen. A 1,2-methyl shift from C-2 to C-1 produces the tertiary cation at C-2 (bearing a methyl group). Loss of the tertiary H on C-1 gives the tetrasubstituted 1,2-dimethylcyclohexene, the Saytzeff product.

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2,2-Dimethylcyclohexanol is heated with concentrated HX3​POX4​. The major alkene and the key step leading to it are

Answer: B

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2,2-Dimethylcyclohexanol is heated with concentrated $H X_{3} PO X_{4}$ . The major alkene and the key step leading to it are