反应详情

温度

-78 °C

To diisopropyl amine (1.54 mL, 11.03 mmol) in THF (22 mL) at −78° C. was added nBuLi (6.89 mL of a 1.6 M solution in hexane). The solution was stirred for 30 min at −78° C., followed by the addition of methyl isobutyrate (0.97 mL, 8.48 mmol). The mixture was stirred at −78° C. for 2 h, and then 1-iodo-4-methyl pentane (1.8 g, 8.48 mmol) and DMPU (0.55 mL, 4.24 mmol) in THF (6 mL) was added. The reaction was stirred at −78° C. and allowed to slowly reach ambient temperature over 16 h. The reaction was quenched by the addition of ammonium chloride (saturated aqueous solution), and the mixture was extracted with EtOAc (2×10 mL). The organics were combined, washed with water, dried (MgSO4), filtered and concentrated. Silica gel chromatography (99/1 hexane/EtOAc) provided 1.57 g of 2,2,6-Trimethyl-heptanoic acid methyl ester. 2,2,6-Trimethyl-heptan-1-ol: 2,2,6Trimethyl-heptanoic acid methyl ester (1.97 g, 10.6 mmol) was taken up in toluene (65 mL) and cooled to −78° C. DiBALH (12.7 mL of a 1 N solution in toluene) was added dropwise. After 45 min, 1.5 mL DiBALH was added. After 2 h, the reaction was quenched by the addition of 15 mL MeOH at −78° C. The mixture was warmed to ambient temperature, and then cooled again to −78° C. for the addition of 10 mL 1 N HCl. The mixture was extracted with EtOAc (3×15 mL). The combined organics were washed with brine, dried (MgSO4), filtered and concentrated. The residual oil was purified via silica gel chromatography (95/5 Hexane/EtOAc) to give 2,2,6-Trimethyl-heptan-1-ol (0.88 g). m/z 159 (M+). 2,2,6-Trimethyl-heptanal: Pyridinium chlorochromate (PCC, 4.17 g, 19.4 mmol) was combined with neutral alumina (14.6 9) in CH2Cl2 and stirred at ambient temperature for 15 min. The alcohol was diluted in CH2Cl2, and the mixture was stirred at ambient temperature for 2 h. The solution was filtered through a pad of silica, and the solids were washed with CH2Cl2. The filtrate was evaporated to give 1.05 g m/z 157 (M+). 2,2,6-Trimethyl-heptanal which was carried on without further purification. 2-Cyano-4,4,8-trimethyl-non-2-enoic acid benzyl ester To a mixture of 2,2,6-Trimethyl-heptanal (1.05 g, 6.73 mmol), piperidine (0.19 mL, 2.01 mmol) and benzyl cyanoacetate (1.29 g, 7.4 mmol) in toluene (50 mL) was added glacial acetic acid (0.72 g, 12.1 mmol). The flask was fitted with a Dean-Stark trap, and the mixture was heated at reflux for 18. The mixture was cooled, treated with dilute HCl, and the layers were separated. The organics were washed with a saturated sodium bicarbonate solution followed by brine, and dried (MgSO4), filtered and concentrated. The residual oil was purified by silica gel chromatography (98/2 hexane/EtOAc) to give 1.3 g of 2-Cyano-4,4,8-trimethyl-non-2-enoic acid benzyl ester m/z 314 (M+). 2-aminomethyl-4,4,8-trimethyl-nonanoic acid: 2-Cyano-4,4,8-trimethyl-non-2-enoic acid benzyl ester (1.3 g, 4.14 mmol) in THF (50 mL) was treated with hydrogen in the presence of 20% Pd/C to give a mixture of the cyano acid and the cyano methyl ester. The mixture was purified by silica gel chromatography to give 278 mg of 80105×41-1-2. The acid was then treated with hydrogen in the presence of Raney Ni in MeOH/NH4OH to give 0.16 g of 2-aminomethyl-4,4,8-trimethyl-nonanoic acid. m/z 230.3 (M+).

1. stirringThe mixture was stirred at −78° C. for 2 h
2. stirringThe reaction was stirred at −78° C.
3. waitallowed to slowly reach ambient temperature over 16 h
4. customThe reaction was quenched by the addition of ammonium chloride (saturated aqueous solution)
5. extractionthe mixture was extracted with EtOAc (2×10 mL)
6. washwashed with water
7. dry with materialdried (MgSO4)
8. filtrationfiltered
9. concentrationconcentrated