Water → HCID 49758888, compound

Participants

Reaction Steps

To a mixture of Example 43A (24.3 g) in tetrahydrofuran (500 mL) at −78° C. was added 2.5 M n-butyllithium (30.3 mL). After 2 minutes, trimethylborate (11.5 mL) was added, and the mixture was allowed to warm to room temperature over 1 hour. The reaction was poured into water, extracted thee times with ethyl acetate, and the combined extracts were washed with brine and concentrated. The crude product was taken up in tetrahydrofuran (200 mL) at 0° C., and 1M aqueous NaOH (69 mL) was added, followed by 30% aqueous H2O2 (8.43 mL), and the solution was stirred for 1 hour. Na2S2O3 (10 g) was added, and the pH was adjusted to 4-5 with concentrated HCl and solid NaH2PO4. The solution was extracted twice with ethyl acetate, and the combined extracts were washed with brine, dried (Na2SO4), filtered, and concentrated. The crude product was chromatographed on silica gel with 5-25% ethyl acetate/hexanes.

Provenance & Evidence