Potassium Carbonate → HCID 10867204, compound

Temperature

-5 °C

To a dry 250 mL round bottom flask were added (S)-Me-CBS (5 mL, 1.0 M in toluene, 5.0 mmol) and 50 mL of THF under argon. The solution was cooled to −5° C. To this solution were added simultaneously BH3.THF (50 mL, 1.0 M in THF, 50 mmol) and ketoester 1 in neat (9.6 g, 50 mmol) via syringe. The addition was completed in 30 min. The reaction mixture was stirred at the same temperature for another 30 minutes and worked up by addition of aqueous K2CO3 solution. After stirring for 30 minutes, the organic layer was separated, and the aqueous layer was extracted with AcOEt. The combined organic layers were washed with brine and dried over (Na2SO4). Revomal of solvent gave a pale yellow oil, containing the hydroester 5 and the CBS catalyst (ca. 11 g). The crude product could be used directly for next reaction. A sample was purified by hydrolysis with 3 N NaOH, and converted into lactone 2 by azeotropically reflux with toluene. E.e was measured by HPLC on lactone 2 (95.6%)

1. additionThe addition
2. stirringAfter stirring for 30 minutes
3. customthe organic layer was separated
4. extractionthe aqueous layer was extracted with AcOEt
5. washThe combined organic layers were washed with brine
6. dry with materialdried over (Na2SO4)
7. customRevomal of solvent gave a pale yellow oil
8. additioncontaining the hydroester 5
9. customA sample was purified by hydrolysis with 3 N NaOH
10. temperatureby azeotropically reflux with toluene

ORD record

ord-1d7d602e3c644955b7caaee0dff261ed

Source dataset

uspto-grants-2006_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07034059B2