Abstract: A process for preparing a compound of formula (V) or its enantiomer, which comprises: (a) reacting racemic aminoindan of formula (II) or its enantiomer with allylhalide in presence of a base and an organic solvent at a temperature ranging from 25 C to the reflux temperature of the solvent to give compound of formula (III); Where R is H or (b) reacting the compound (III) with halogenating agent in a suitable organic solvent to give a dihalo compound of formula (IV). (c) treating the dihalo compound (IV) with a suitable base to give compound (V).