Lithium Hydroxide → HCID 11488860, compound

Participants

Reaction Steps

To a solution of the above ester (1 eq) in a 3.5/1 mixture of THF/MeOH (0.25M) at 0° C. was slowly added aqueous LiOH 1N (1 eq) and the mixture was stirred at 0° C. for 16 h or until almost complete hydrolysis of the ester; under these conditions, the other minor diastereomer has a much slower rate of hydrolysis. AcOH was added and the solvent was removed in vacuo. The residue was taken up in EtOAc/H2O and the organic layer was washed with brine, dried over Na2SO4 filtered and concentrated. To remove the unreacted methyl ester, the residue was filtered through a pad of silica gel eluting first with 10% EtOAc/toluene and then with 60% EtOAc/toluene containing 1% of AcOH. The residue was swished in 30% EtOAc/hexane and dried under high vacuum at 50° C. for 16 hr to give the desired title compound as a white solid with de and ee >95% (checked by chiral HPLC). MS (−APCI) m/z 496.0 (M−H)−. [α]D=−181° in MeOH.

Provenance & Evidence