Iodine → Lithium diisopropylamide mono(tetrahydrofuran)

Temperature

-20 °C

LDA/THF was prepared by adding n-BuLi (1.6 M, 1.31 mL, 2.10 mmol, 1.5 equiv) to diisopropylamine (0.30 mL, 2.10 mmol) in THF (5 mL) at −78° C. The reaction mixture was warmed to −20° C. and stirred for 10 min. After the LDA solution was cooled to −78° C., compound S23-1 (0.52 g, 1.40 mmol) in THF (2 mL) was added dropwise, forming an orange-red solution. After 10 min, a solution of iodine (0.76 g, 2.97 mmol, 2.1 equiv) in THF (2 mL) was added dropwise to the above reaction mixture. The reaction solution was allowed to warm to −15° C. in 1 h and quenched by saturated aqueous NH4Cl. LC/MS indicated that the starting material was all consumed. The reaction mixture was diluted with EtOAc (100 mL), washed with a 5% sodium thiosulfate solution (2×30 mL), water and brine, dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting crude oil was purified by flash column chromatography (Silicycle 12 g column, 1% to 5% EtOAc in hexanes gradient), to provide S23-2 (0.56 g, 80%): 1H NMR (400 MHz, CDCl3) δ 7.48-7.43 (m, 2 H), 7.39-7.32 (m, 5 H), 7.28-7.22 (m, 1 H), 7.05-6.99 (m, 2 H), 5.08 (s, 2 H), 2.39 (d, J=2.4 Hz, 3 H); MS (ESI) m/z 495.03 (M−H).

1. customforming an orange-red solution
2. waitAfter 10 min
3. temperatureto warm to −15° C. in 1 h
4. customquenched by saturated aqueous NH4Cl
5. additionThe reaction mixture was diluted with EtOAc (100 mL)
6. washwashed with a 5% sodium thiosulfate solution (2×30 mL), water and brine
7. dry with materialdried over sodium sulfate
8. filtrationfiltered
9. concentrationconcentrated under reduced pressure
10. customThe resulting crude oil was purified by flash column chromatography (Silicycle 12 g column, 1% to 5% EtOAc in hexanes gradient)
11. customto provide S23-2 (0.56 g, 80%)

ORD record

ord-e6dedbd413744276b27de9cea74f1f56

Source dataset

uspto-grants-2016_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09315451B2