How do you create primary amines from alcohols?

Question

By a primary amine I mean a compound where the hydroxyl group of the corresponding alcohol is replaced with an amine group.

Answer 1

Typically a substitution creating a primary amine utilizes NH3, but hydroxyl's alone are poor leaving groups. If they're catalyzed by an acid, become tosylates, or are converted to an alkyl halide, they can be manipulated to form other products.. If you convert your hydroxyl group to a good leaving group like bromine(PBr3) or to a chlorine(SOCl2), then use your NH3, you'll form your product.

Answer 2

One method is to react the alcohol with PCl₃ or PBr₃ to form and alkyl halide. Then react the alkyl halide with ammonia to form the primary amine. The sequence of reactions can be written as:

(1) R−OH + PBr₃ → R−Br

(2) R−Br + NH₃ → R−NH₂