2,2-Dimethoxypropane → [1-{5-[1-Benzyloxycarbonylamino-2-(4-tert-butoxy-phenyl)-ethyl]-2,2-dimethyl-[1,3]dioxolan-4-yl}-2-(4-tert-butoxy-phenyl)-ethyl]-carbamic Acid Benzyl Ester

Participants

Reaction Steps

Diol 2.5 (5 g, 7 mmol) is dissolved in acetone (120 mL), 2,2-dimethoxypropane (20 mL), and pyridinium p-toluenesulfonate (120 mg, 0.5 mmol). The resulting solution is refluxed for 30 min., and then concentrated under reduced pressure to almost dryness. The resulting mixture is partitioned between methylene chloride and saturated NaHCO3 aqueous solution, dried, concentrated under reduced pressure, and purified by silica gel column chomatography to afford isopropylidene protected diol 2.6 (4.8 g, 92%).

Provenance & Evidence