A method of preparing a tetrabenazine compound (TBZ compound) having structure I comprising the steps of reacting a nucleophilic alkenyl species with aldehyde compound II and oxidizing the resultant allylic alcohol to provide enone III. The protecting group P1 on the tetrahydroisoquinoline nitrogen is removed and the resultant deprotected intermediate is induced to undergo an amino cyclization reaction to provide a product TBZ compound having structure I. The method may be used to prepare either enantiomeric form of tetrabenazine; (+)-tetrabenazine or (−)-tetrabenazine. Alternatively the method may be adapted to provide a mixture enriched in one tetrabenazine enantiomer, a racemic mixture, or a diastereomeric mixture of tetrabenazine compounds. In addition, the present invention provides novel synthetic intermediate compositions which may be used to prepare either or both enantiomers of tetrabenazine, derivatives of tetrabenazine, and analogs of tetrabenazine.