Chapter 11.10A, Problem 11.23P

Some alcohols undergo rearrangement or other unwanted side reactions when they dehydrate in acid Alcohols may be dehydrated under mildly basic conditions using phosphorus oxychloride (POCl₃) in pyridine. The alcohol reacts with phosphorus oxychloride much like it reacts with tosyl chloride (Section11-5), displacing a chloride ion from phosphorus to give an alkyl dichloroptrosphate ester. The dichlorophosphate group is an outstanding leaving group. Pyridine reacts as a base with the dichlorophosphate ester to give an E2 elimination. Propose a mechanism for the dehydration of cyclohexanol by POCl₃ in pyridine.