Reaction #42725

Reaction equation

methanol

8-Benzyloxy 5-(2-bromoacetyl)-1H-quinolin-2-one

tetrahydrofuran

Borane

→

title compound

Yield 81.0%

8-Benzyloxy-5-((R)-2-bromo-1-hydroxyethyl)-1H-quinolin-2-one

Yield 81.0%

Solvents

toluene

Conditions

Workup

1. 1
   ConcentrationThe mixture was concentrated under vacuum
2. 2
   workup.DISSOLUTIONthe residue was dissolved
3. 3
   Filtrationfiltered while hot and
4. 4
   Temperaturethen cooled to room temperature
5. 5
   FiltrationThe crystals were filtered
6. 6
   Washwashed with acetonitrile
7. 7
   Otherdried under vacuum

Procedure

8-Benzyloxy 5-(2-bromoacetyl)-1H-quinolin-2-one (90.0 g, 243 mmol) was placed under nitrogen and tetrahydrofuran (900 mL) was added followed by the catalyst described above (1.8 M in toluene, 15 mL, 27 mmol). The suspension was cooled to −10±5° C. in an ice/isopropanol bath. Borane (1.0 M in THF, 294 mL, 294 mmol) was added over 4 h. The reaction was then stirred an additional 45 min at −10° C. and then methanol (250 mL) was added slowly. The mixture was concentrated under vacuum and the residue was dissolved in boiling acetonitrile (1.3 L), filtered while hot and then cooled to room temperature. The crystals were filtered, washed with acetonitrile and dried under vacuum to give the title compound (72.5 g, 196 mmol, 81% yield, 95% ee, 95% pure by HPLC).

Source