Q17-62E - Organic Chemistry (Mcmurry)

Question

Testosterone is one of the most important male steroid hormones. When testosterone is dehydrated by treatment with acid, rearrangement occurs to yield the product shown. Propose a mechanism to account for this reaction.

Step-by-Step Solution

Answer

The mechanism of the reaction is as follows:

Step1: Protonation of the alcohol group

One of the most significant male steroid hormones is testosterone. When testosterone is dehydrated by treatment with acid, rearrangement occurs to yield the product shown. Propose a mechanism to account for this reaction.

The mechanism of the reaction is as follows:

The first step of the mechanism is a protonation of the alcohol group by the proton.

The reaction is as follows:

Step2: Then water group leaves

The positively charge water group then leaves and forms a carbocation.

The reaction is as follows:

Step3: Secondary carbocation compound undergoes 1,2-methyl shift

The secondary carbocation compound undergoes 1,2-methyl shift to form a more stable tertiary carbocation.

The reaction is as follows:

Step4: Tertiary carbocation molecule loses a proton

The tertiary carbocation molecule loses a proton to form the more substituted carbon atom to form the final product.

The reaction is as follows: