Potassium Carbonate → HCID 10867204, compound

Participants

Reaction Conditions

Reaction Steps

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%)

Provenance & Evidence