Q8-4P - Organic Chemistry (Mcmurry)

Question

Question: Addition of HCl to 1,2-dimethylcyclohexene yields a mixture of two products. Show the stereochemistry of each, and explain why a mixture is formed.

Step-by-Step Solution

Answer

Answer

The mixture of products formed is,

Step 1: Addition of HCl to cyclohexene

The addition of HCl to cyclohexene yields a mixture of products, in which H and Cl are added to a cis or trans alkene. A carbocation intermediate is formed, then attacked by a chloride ion.

Step 2: The mixture of products formed and its stereochemistry

The addition of HCl (hydrogen halide) to cyclohexene involves the formation of a halonium ion intermediate. A chloride ion attacks this carbocation either from the top or bottom. This reaction yields a mixture of products in which the two methyl groups can be either cis or trans to each other.

                                   Addition of HCl to 1,2-dimethylcyclohexene