# SN2 vs SN1 in Acidic Environments for Secondary Alkyl Halides

I have researched three books: Brown's, Solomons' and Wade's. I could not find enough information about this.

My prof. says that secondary alkly halides undergo SN1 only under acidic environments.

We had this quiz. I got a terrible mark on one question.

I think these are the missing structures.

Now, I am wondering, did Sn2 occur here, if yes, at what rate? Was it more important than Sn1? What was the major pathway?

What is the major pathway for all secondary alkyl halides with acidic environment and with NONacidic environments?

Could anyone also just check my missing structures?

• It is an SN1 reaction. Your major error was forgetting the double bond in the product. – jerepierre Nov 2 '14 at 0:36
• Jerepierre, yes I forgot the double bonds on my exam. BUT, there is also the fact that there can be carbocation rearrangement. The double bond moves away. (I actually made a mistake on the uploaded images too. The double bond must be on the adjacent carbon.) – yolo123 Nov 2 '14 at 2:08

Note that the starting material is drawn as a chiral molecule. Solvolysis of this starting material will generate a symmetric, achiral, allylic carbocation. Since a stabilized allylic carbocation is generated, the mechanism likely proceeds through an $\ce{S_{N}1}$ mechanism.