Compound (I) (intermediate no. (VIII) in scheme no. 19918301a) is a key intermediate in the synthesis of indinavir. For the synthesis of the product 285239, (I) is coupled with benzofuran-2-carbaldehyde (II) via a reductive amination by means of NaBH(OAc)3 either in 1,2-dichloroethane/AcOH or in isopropyl acetate/AcOH.