تفاعل #57064

معادلة التفاعل

n-BuLi

Methyl 5-methylhexanoate

5-methylhexanoic acid

sulfuric acid

dimethyl methylphosphonate

→

product

المردود 76.2%

Dimethyl 6-methyl-2-oxoheptylphosphonate

المردود 76.2%

المذيبات

methanol

THF

ظروف التفاعل

المعالجة

1. 1
   workup.ADDITIONwas added dropwise for 10 minutes
2. 2
   workup.STIRRINGThe mixture was stirred for 2 hours at −78° C.
3. 3
   أخرىThe mixture was quenched with addition of 1N HCl to pH 4-5
4. 4
   أخرىThe organic layer was separated
5. 5
   غسيلwashed with brine
6. 6
   تجفيفdried over MgSO4
7. 7
   أخرىThe residue was purified through flash chromatography on silica gel (EtOAc:Hexanes=1:1)

الإجراء التجريبي

To a solution of dimethyl methylphosphonate (2.17 ml, 20 mmol) in anhydrous THF (20 mL), cooled at −78° C. was added n-BuLi (1.6 M in hexane, 13.7 mL, 22 mmol). The mixture was stirred for 30 minutes at this temperature under nitrogen. Methyl 5-methylhexanoate (1.44 g, 10 mmol), prepared from 5-methylhexanoic acid (from Avocado) and methanol at the presence of the catalytic amount of the concentrated sulfuric acid (the procedure described in Intermediate 17.1), was added dropwise for 10 minutes. The mixture was stirred for 2 hours at −78° C., gradually was warm to room temperature. The mixture was quenched with addition of 1N HCl to pH 4-5. The organic layer was separated, washed with brine and dried over MgSO4. The residue was purified through flash chromatography on silica gel (EtOAc:Hexanes=1:1) to give the product (1.80 g) with colorless oil in 76% yield. 1HNMR (CD3OD, ppm) δ 0.866 (d, J=6.5 Hz, 6H), 1.16 (m, 2H), 1.56 (m, 3H), 2.58 (t, J=7.3 Hz, 2H), 3.10 (d, J=22.7 Hz, 2H), 3.70 (s, 3H), 3.79 (s, 3H)

المصدر