反应详情

Anhydride 1 (3.85 g; 25 mmol) was combined with trimethyl orthoformate (4.10 mL; 37.5 mmol; 1.5 equiv) and methanol (8.2 mL). p-Toluenesulfonic acid (238 mg; 1.25 mmol; 0.05 equiv) was added and the reaction mixture was stirred overnight at ambient temperature to completely consume 1 and afford a single product by GC analysis. The solvent was removed at reduced pressure and the residue was dissolved in ethyl acetate (30 mL), washed with saturated aqueous NaHCO3 (10 mL), dried over MgSO4, and concentrated to afford 4.91 g (98%) of cis-2a which gave a single peak by GC analysis.

1. customto completely consume 1
2. customafford a single product by GC analysis
3. customThe solvent was removed at reduced pressure
4. dissolutionthe residue was dissolved in ethyl acetate (30 mL)
5. washwashed with saturated aqueous NaHCO3 (10 mL)
6. dry with materialdried over MgSO4
7. concentrationconcentrated
8. customto afford 4.91 g (98%) of cis-2a which
9. customgave a single peak by GC analysis