The present invention provides a process for preparing a compound of formula (Vl) or a salt thereof, the process comprising: (i) reacting 4-methoxyphenyl acetone with an amine of formula (VIII) under conditions of reductive amination to produce a compound of formula (II) or a salt thereof, wherein there is no isolation of an imine intermediate formed during the reductive amination； (ii) condensing the compound (II) or the acid addition salt thereof with an α-haloketone of formula (III) to produce the compound of formula (IV)； (iii) reducing the compound (IV) to a compound of formula (V)； and (iv) reducing the compound (V) to the compound of formula (Vl), wherein the reduction is carried out in the presence of either (1 ) a hydrogen donating compound in the presence of a hydrogen transfer catalyst； or (2) ammonium formate using a hydrogenation catalyst, wherein: R1 and R2 are independently optionally substituted arylalkyl, and Hal is selected from chloro or bromo.
