تفاعل #1174777

معادلة التفاعل

ethyl acetate

HCl

Boc-L-leucinal

n-butyllithium

hexane

diisopropylamine

→

desired product

المردود 38.8%

4-t-Butyloxycarbonylamino-3-hydroxy-6-methylheptanoic acid ethyl ester

المردود 38.8%

المذيبات

tetrahydrofuran

tetrahydrofuran

ظروف التفاعل

المعالجة

1. 1
   أخرىlowered to -78 degrees C
2. 2
   درجة الحرارةwhile maintaining the temperature below -75 degrees C
3. 3
   workup.STIRRINGThe solution was stirred 10 min
4. 4
   workup.WAITAfter 30 min
5. 5
   استخلاصand extracted with ether (3×200 mL)
6. 6
   استخلاصThe combined ethereal extract
7. 7
   غسيلwas washed with saturated sodium chloride
8. 8
   تجفيفdried with magnesium sulfate
9. 9
   ترشيحfiltered
10. 10
    أخرىEvaporation of the filtrate in vacuo
11. 11
    أخرىgave 14 g of crude product which
12. 12
    أخرىwas purified by flash chromatography (20% ethyl acetate in hexane)

الإجراء التجريبي

To diisopropylamine (7.7 g, 0.077 mol) in dry tetrahydrofuran (26 mL) cooled to -20 degrees C. under argon was added dropwise n-butyllithium in hexane (1.46M, 52.4 mL, 0.077 mol). The solution was stirred 15 min, the temperature lowered to -78 degrees C. and dry ethyl acetate (6.7 g, 0.077 mol) added dropwise while maintaining the temperature below -75 degrees C. The solution was stirred 10 min and a precooled (-78 degrees C.) tetrahydrofuran solution of Boc-L-leucinal (11 g, 0.051 mol) was added. After 30 min, 2M HCl (40 mL) was added and the mixture was slowly warmed to 10 degrees C. and extracted with ether (3×200 mL). The combined ethereal extract was washed with saturated sodium chloride and dried with magnesium sulfate and filtered. Evaporation of the filtrate in vacuo gave 14 g of crude product which was purified by flash chromatography (20% ethyl acetate in hexane) to give 6 g of desired product.

المصدر