Synthesis of 9-fluorenylmethoxycarbonyl-protected amino aldehydes

9-Fluorenylmethoxycarbonyl-protected amino aldehydes could be efficiently prepared in good yields by using two methods: (i) NaBH4 reduction of Fmoc-protected mixed anhydrides, followed by the Swern oxidation of the alcohols; and (ii) LiAlH4 reduction of Fmoc-protected amino acid Weinreb amides. Both methods afforded comparable overall synthetic yields (70–80%).