Reaktion #6619

Reaktionsgleichung

THF

diisopropylamine

methyllithium

II

(4S,5S)-2-ethyl-4-methoxymethyl-5-phenyl-2-oxazoline

THF

lithium diisopropylamide

bromide

THF

sodium chloride

compound II

(4S,5S)-2-ethyl-4-methoxymethyl-5-phenyl-2-oxazoline

THF

→

2-(1-methyl-4-isobutylphenyl)-4-methoxymethyl-5-phenyl-2-oxazoline

Ausbeute 90.0%

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeis prepared
2. 2
   workup.ADDITIONadded
3. 3
   workup.WAITis continued for half an hour at -75° C.
4. 4
   workup.STIRRINGThe resulting, colorless solution is stirred at this temperature for one hour
5. 5
   Sonstigeto reach 20° C
6. 6
   Extraktionextracted with several portions of petrolether or ether
7. 7
   Trocknendried over Na2SO4 or molecular sieves, (4.0 Å)
8. 8
   workup.DISTILLATIONdistilled in vacuo at 0.1 mm Hg

Vorschrift

A solution of the compound II (155 g, 0.71 mol) in THF (1.6 L) under nitrogen is cooled to -75° C. in a dry-ice-acetone bath. A solution of 0.8 mol of lithium diisopropylamide, derived from 98 ml of diisopropylamine and 300 ml of 2,3M butylithium (methyllithium) in 750 ml of dry THF is prepared, and added under continuous stirring in the presence of 4.0 Å molecular sieves to the solution of II in dry THF. Stirring is continued for half an hour at -75° C. and 4isobutylphenyliode (bromide) of the amount of 237.6 g (1.95 mol) in 300 ml THF (dry) is added over a period of time of 10 minutes. The resulting, colorless solution is stirred at this temperature for one hour, then subsequently permitted to reach 20° C. The reaction mixture is poured into 3L of saturated aqueous sodium chloride solution, extracted with several portions of petrolether or ether, dried over Na2SO4 or molecular sieves, (4.0 Å) and distilled in vacuo at 0.1 mm Hg to yield 90% of 2-(1-methyl-4-isobutylphenyl)-4-methoxymethyl-5-phenyl-2-oxazoline, having [α]24 -40.5° (c 10.1 in CHCl3) IR (film) 1671 cm-1, NMR (CDCl3, TMS) δ7.33 (s, 5H), 5.33 (d, J=7HZ, 1H), 4.33-3.93 (9, 1H), 3.80-3.33 (m, 2H) 3.43 (3H), 2.87-2.33 (m, 1H), and 2.00-0.68 (m, 12H).

Quelle