Figure 1
Figure 1: Epoxides I,II,III,IV
-Which of the following epoxides in Figure 1 is/are optically active?

Question

Figure 1
Figure 1: Epoxides I,II,III,IV 
-Which of the following epoxides in Figure 1 is/are optically active?

Quizplus · Accepted Answer

Epoxides are optically active only when there are two different substituents attached to the two carbon atoms in the epoxide ring. 
Epoxide I has the same substituent (methyl) attached to both carbon atoms and is therefore not optically active. 
Epoxide IV does have two different substituents, but they are both on the same carbon atom, making it not optically active. 
Epoxides II and III, however, have two different substituents attached to different carbon atoms in the epoxide ring, making them optically active.

Figure 1 Figure 1: Epoxides I,II,III,IV