Question

Construct a three-step synthesis of 1,2-epoxycyclopentane from cyclopentanol by dragging the appropriate formulas into the bins. Note that each bin will hold only one item, and not all of the given reagents or structures will be used.

Answer 1

Answer:

(1) Bromination, (2) E2 elimination and (3) epoxidation

Explanation:

• In the first step, -OH group in cyclopentanol is replaced by more facile leaving group Br by treating cyclopentanol with $PBr_{3}$

• In the second step, E2 elimination in presence of strong base e.g. NaOEt/EtOH produce cyclopentene

• In the third step, treatment of cyclopentene with mCPBA produces 1,2-epoxycyclopentane

• Full reaction scheme has been shown below