Potassium;tri(butan-2-yl)boranuide → HCID 10348167, compound

Participants

Reaction Conditions

Reaction Steps

K-Selectride® (potassium tri-sec-butylborohydride) (8.9 ml, 1M in THF, 8.9 mmol) was added dropwise via syringe to a solution of ketone 2005 (1.7 g, 3.0 mmol) in dry THF (50 ml) at room temperature under argon. The reaction mixture was heated to 500° C. in an oil bath and stirred for 5 hours. The mixture was allowed to cool to room temperature and then quenched by adding 30% H2O2 dropwise until the evolution of gas ceased. Saturated aqueous NH4Cl solution was added and the aqueous solution was extracted (3×) with Et 20. The combined organic extracts were washed with aqueous saturated NaHCO3 solution (2×), distilled H2O (2×), and aqueous saturated NaCl solution, dried over anhydrous MgSO4, filtered, and the solvent was removed in vacuo. The crude product was purified by flash chromatography (SiO2, hexanes:EtOAc 10:1) giving alcohol 2006 as a white solid (1.6 g, 94%). 1H NMR (500 MHz, CDCl) δ 4.73-4.66 (m, 1 H, THP methine H), 3.95-3.85 (m, 1 H, THP CH2), 3.82 (s, 1 H, C-7 H), 3.66-3.52 (m, 3 H, THP CH2C & C-24 H), 3.50-3.45 (m, 1H, C-3 H), 1.08 (s, 3H, C-19 H), 0.91 (d, J=6.6 Hz, C-21 H), 0.89 (s, 9 H, t-Bu), 0.64 (s, 3 H, C-18 H), 0.04 (s, 6 H, TBDMS CH3); MS (CI/isobutane) m/z 577 (M+1, 5%), 493 (M+1-THP, 22%), 475 (M+1-THPOH, 26%), 458 (M+1-THPOH-H2O, 38%), 343 (M+1-THPOH-TBDMSOH, 80%), 325 (M+1-THPOH-TBDMSOH-H2O, 100%); IR (CHCl3) 3430, 2860 cm-1 ; m.p. 130°-133° C.; Anal. calcd. for C35H64 O4Si: C=72.86, H=11.18; Found: C=72.69, H=11.32.

Provenance & Evidence