Acetic Acid → HCID 10881559, compound

Participants

Reaction Steps

To a solution of LHMDS (1.0 M, 24.2 mL, 24.2 mmol) in THF was added indole lactone 11 (3.00 g, 11 mmol) in freshly distilled THF (33 mL) at -78° C. The light yellow solution was stirred for 40 min, and triisopropylbenzenesulfonyl azide (3.40 g, 11 mmol) in 33 mL dry THF was added at -78° C. via syringe. The reaction mixture was stirred for 20 min before quenching with acetic acid (49.5 mmol, 2.83 mL). The reaction mixture was allowed to warm to room temperature over 30 min before being diluted with saturated NH4C1 solution. This solution was stirred for 5 min and extracted with EtOAc (2×75 mL). The combined organic layers were dried (MgSO4), and the solvent was removed under reduced pressure. The crude oil was flash chromatographed on silica gel (1:2, EtOAc-hexanes eluant) to afford 2.21 g (64%) of pure azido lactone 12 as a mixture of diastereomers (3:2; SS/RR:SR/RS). A sample was crystallized from ethyl acetate/hexanes: mp. 110-112° C., SS/RR recemate; 1H NMR (300 MHz, CDC13) δ 2.19 (dd, 1H, J=14.0, 7.3 Hz), 2.63 (dd, 1H, J=14.0, 9.3 Hz), 3.34 (dd, 1H, J=9.0, 2.6 Hz), 3.39 (ABq, 2H, J=15.3 Hz), 3.84 (s, 3H), 7.10 (d, J=2.4 Hz), 7.14-7.24 ((m, 2H), 7.37 (d, 1H, J=8.3 Hz), 7.63 (d, 1H, J=7.6 Hz), 8.32 (brs 1H, D2O Exchangeable).

Provenance & Evidence