To a stirred solution of ammonium salt (1.0 equiv.) and aldehyde (1.0 equiv.) in DCE (0.1 M) was added NEt3 (2.0 equiv.) and the mixture was stirred for 5 to 15 min at room temperature. After this time, NaBH(OAc)3 (1.4 equiv.) was added to the mixture, which was stirred for 16 h to 20 h at room temperature. After addition of a saturated aqueous solution of NaHCO3, the organic layer was separated and the aqueous layer was extracted with DCM.