반응 #92884

반응 방정식

di-isobutylaluminium hydride

Rochelle salt

Boc--L--Leucine methyl ester

MeOH

→

aldehyde

Boc--L--Leucinal

용매

toluene

H2O

toluene

반응 조건

후처리

1. 1
   기타under -70°
2. 2
   workup.ADDITIONat -78° after completion of the addition
3. 3
   workup.STIRRINGThis mixture was shaken until an extractable solution
4. 4
   기타was obtained
5. 5
   기타The toluene was separated
6. 6
   추출the aqueous phase re-extracted with ether (2×300 ml)
7. 7
   건조dried (Na2SO4)
8. 8
   기타was passed rapidly through a pad of silica gel in 15% EtOAc/petrol 40°-60°

실험 절차

Boc--L--Leucine methyl ester (22.7 g, 90 mmoles) in dry toluene (250 ml) under N2 was cooled to -78° and 25% di-isobutylaluminium hydride in toluene (130 ml, 225 mmoles) were added over 25 mins. keeping the temperature under -70°. The mixture was stirred for 15 mins. at -78° after completion of the addition, then MeOH (10 ml) was added cautiously. When effervescence ceased the mixture was poured into an ice-cold solution of Rochelle salt (100 ml of saturated solution+600 ml H2O). This mixture was shaken until an extractable solution was obtained. The toluene was separated and the aqueous phase re-extracted with ether (2×300 ml). Toluene and ether extracts were combined and dried (Na2SO4). The resulting oil was passed rapidly through a pad of silica gel in 15% EtOAc/petrol 40°-60°. The crude aldehyde was obtained as an oil, weight 18.68 g. Nmr showed aldehyde content to be 85%, therefore yield of aldehyde: 15.9 g (83%).

출처