تفاعل #433084

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 (1.46 M, 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, 2 M 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