Scheme 1. Synthesis of aminoalcohol 7a. Reagents and reaction conditions: (a) 1. CDI, CH₂Cl₂, rt, 45 min; 2. CH₃NHOCH₃, CH₂Cl₂, rt, 24 h, 89%. (b) DIBAL-H, toluene, –78 °C, 2 h. (c) (C₆H₅)₃P CHCO₂Et, CH₂Cl₂, rt, 24 h, 80%. (d) Benzylamine, EtOH, 80 °C, 20 h, 42%. (e) TosCl, DIPEA, CH₂Cl₂, rt, 24 h, 87%. (f) 0.1 M NaOH, THF/H₂O, rt, 26 h, 69%. (g) P₄O₁₀, CH₂Cl₂, –10 °C, 23 h, 27%. (h) NaBH₄, MeOH, 0 °C to rt, 5.5 h, 78%. (i) Mg⁰, MeOH, rt, ultra-sonic, 5 h, 64%.