Sometimes the strongly basic properties of Grignard reagents can be turned to synthetic advantage. A chemist needed samples of butane specifically labeled with deuterium, the mass 2 isotope of hydrogen, as shown:
(a) CH3CH2CH2CH2D
(b) CH3CHDCH2CH3
Suggest methods for the preparation of each of these using heavy water (D2O) as the source of deuterium, butanols of your choice, and any necessary organic or inorganic reagents.