反应详情

温度

0 °C

To a solution of 5-bromo-7-tert-butyl-2,3-dihydro-3,3-dimethylbenzofuran (500 mg, 1.8 mmol) in Et2O (0.6 mL), and hexanes (5.5 mL) at -78° C. is added t-BuLi (1.5M in hexanes, 2.9 eq, 5.3 mmol, 3.3 mL) at such a rate that the reaction temperature does not exceed -60° C. This solution is stirred for 1 h and then slowly cannulated into a -78° C. solution of dimethylcyanamide (1.0 eq, 1.8 mmol, 0.15 mL) in Et2O (5 mL). The reaction is kept at -78° C. for 0.5 h and then is allowed to warm to 0° C. After 1.5 h, TLC (10% MeOH in CHCl3) indicates the reaction to be complete. The reaction is quenched with H2O (10 mL) and 1N HCl (10 mL) and then extracted with Et2O (2×10 mL). The aqueous layer is brought to pH 9 with 1N NaOH and extracted with Et2O (3×15 mL), which is dried (MgSO4) and evaporated to a yellow oil (410 mg). This oil is purified by preparative TLC (15% MeOH in CHCl3) to give a yellow oil, which is stirred in EtOH (5 mL) and 1N HCl (10 mL) for 5 min. The EtOH is evaporated and the resulting solution extracted with CH2Cl2 (3×10 mL). The dried organic layers are evaporated to a yellow oil, which is triturated with Et2O to give the title compound as a white powder (110 mg, 19.7%), mp>160° C. (dec).

1. customdoes not exceed -60° C
2. customslowly cannulated into a -78° C.
3. waitThe reaction is kept at -78° C. for 0.5 h
4. waitAfter 1.5 h
5. customthe reaction
6. customThe reaction is quenched with H2O (10 mL) and 1N HCl (10 mL)
7. extractionextracted with Et2O (2×10 mL)
8. extractionextracted with Et2O (3×15 mL), which
9. dry with materialis dried (MgSO4)
10. customevaporated to a yellow oil (410 mg)
11. customThis oil is purified by preparative TLC (15% MeOH in CHCl3)
12. customto give a yellow oil, which
13. customThe EtOH is evaporated
14. extractionthe resulting solution extracted with CH2Cl2 (3×10 mL)
15. customThe dried organic layers are evaporated to a yellow oil, which
16. customis triturated with Et2O