A mixture of Intermediate 95a (0.50 g, 2.2 mmol) in dry THF (17 mL) was treated with triphenylphosphine (1.13 g, 4.32 mmol) and (R)-(−)-1-benzyloxy-2-propanol (0.52 mL, 3.24 mmol) then diisopropylazodicarboxylate (0.85 mL, 4.32 mmol) was added dropwise (the reaction mixture became very warm). After stirring at ambient temperature for 1.75 h the mixture was treated with water (0.2 mL) then concentrated in vacuo to a viscous orange oil. The oil was purified by FCC, using 0-7% EtOAc in DCM. The resulting oil was purified further by FCC, using 0-30% EtOAc in cyclohexane. The product was applied to a pre-conditioned (with MeOH)SCX-2 cartridge and eluted with MeOH then 2N NH3 in MeOH. The product containing fractions were combined and concentrated in vacuo to give the title compound as a viscous golden oil (0.39 g, 48%). LCMS (Method 3): Rt 3.77 min, m/z 380.4 [MH+].
