反应详情

Ethyl diazoacetate (0.5 mL, 5.0 mmol) was added dropwise to a solution of 2,5-dihydrofuran (1.3 g, 19 mmol) and rhodium(II) acetate dimer (100 mg, 0.24 mmol) in methylene chloride (15 mL) —caution: gas evolution. The reaction mixture was stirred for 16 hours at room temperature, and then diluted with methylene chloride (50 mL) and washed with water (50 mL). The organic layer was separated, dried over sodium sulfate, filtered, and evaporated in vacuo to afford a residue that was redissolved in methanol (20 mL) and treated with lithium hydroxide (170 mg, 7.1 mmol). The mixture was stirred at room temperature for 3 hours, and then diluted with methylene chloride (100 mL), 1.0N sodium hydroxide solution in water (15 mL) and water (10 mL). The aqueous layer was separated, acidified to pH 3 via addition of solid citric acid, and then extracted with methylene chloride (100 mL). The organic layer was separated, dried over sodium sulfate, filtered, and evaporated in vacuo to afford a yellow solid that was used in the next step without further purification.

1. washwashed with water (50 mL)
2. customThe organic layer was separated
3. dry with materialdried over sodium sulfate
4. filtrationfiltered
5. customevaporated in vacuo
6. customto afford a residue that
7. stirringThe mixture was stirred at room temperature for 3 hours
8. customThe aqueous layer was separated
9. additionacidified to pH 3 via addition of solid citric acid
10. extractionextracted with methylene chloride (100 mL)
11. customThe organic layer was separated
12. dry with materialdried over sodium sulfate
13. filtrationfiltered
14. customevaporated in vacuo
15. customto afford a yellow solid that
16. customwas used in the next step without further purification