Reagents and conditions: (a) p-methoxybenzaldehyde dimethylacetal (6.5 eq), CSA (cat), CH2Cl2, 23 °C, 24 h, 82%; (b) p-methoxybenzyl bromide (4 eq), NaH, DMF, 0 → 23 °C, 40 min, 91%; (c) Bu4F, 23 °C, 2 h, THF, 96%; (d) 7 (1.7 eq), DCC (2.6 eq), DMAP (2.1 eq), 23 °C, 30 min, EtOAc, 93%; (e) TFA, 23 °C, 2 h, CH2Cl2, MeOH, 91%; (f) DCC (4.7 eq), 23 °C, 30 min, CH2Cl2, H2O, 82%.