was submitted to the one-pot tandem reduction–olefination procedure described above. Disappointingly, the product (E)-4a was obtained in low yield although in excellent (dia)stereoselectivity. In the synthesis of anti-2-amino-1,3- diols, we reported earlier that the addition of DIBAL-H must be done necessarily in two portions [16]. Thus, fine-tuning of the reduction conditions was required in order to improve the yield, as shown in Table 3.