Total number of possible isomers (both structural as well as stereoisomers) of cyclic ethers of molecular formula C4H8O is :
- 10
- 11
- 6
- 8
Answer
(1) 10
Solution
Cyclic ethers of C4H8O (ring containing O): six structural isomers
[figure]
(i) Oxolane (tetrahydrofuran): no chiral carbon → 1
(ii) 2-Methyloxetane: one chiral carbon → pair of enantiomers → 2
(iii) 3-Methyloxetane: no chiral carbon → 1
(iv) 2-Ethyloxirane: one chiral carbon → pair of enantiomers → 2
(v) 2,2-Dimethyloxirane: no chiral carbon → 1
(vi) 2,3-Dimethyloxirane: cis (meso) 1 + trans (pair of enantiomers) 2 → 3
∴ Total number of isomers = 1 + 2 + 1 + 2 + 1 + 3 = 10
Answer: (1)