15. Analytical Techniques:IR, NMR, Mass Spect
Structure Determination without Mass Spect
3PRACTICE PROBLEM
When 2-chloro-2,3-dimethylbutane is treated with different strong bases then elimination causes the formation of two isomers (A and B) with formula C6H12. When sodium hydroxide is used as a base then the major product is isomer A and when tert-butoxide is used as a base then the isomer B is formed in a higher quantity.
a. Determine the structures of the two isomers using the NMR spectra given below.
b. Explain why isomer A predominates when sodium hydroxide is used while isomer B predominates when tert-butoxide is used.
![](https://lightcat-files.s3.amazonaws.com/problem_images/d42af982e6515c2e-1672075424650.jpg)
When 2-chloro-2,3-dimethylbutane is treated with different strong bases then elimination causes the formation of two isomers (A and B) with formula C6H12. When sodium hydroxide is used as a base then the major product is isomer A and when tert-butoxide is used as a base then the isomer B is formed in a higher quantity.
a. Determine the structures of the two isomers using the NMR spectra given below.
b. Explain why isomer A predominates when sodium hydroxide is used while isomer B predominates when tert-butoxide is used.