A number of drugs are prepared by reactions in which carbon-carbon bond formation is the l...

A number of drugs are prepared by reactions in which carbon-carbon bond formation is the last step. Indicate what you believe would be a reasonable last step in the synthesis of each of the following:

(a)  Mepaifynol, a mild hypnotic or sleep-inducing agent

(b)  Diphepanol, an antitussive (cough suppressant)

(c)  Mestranol, an estrogenic component of oral contraceptive drugs