Boron trifluoride etherate → HCID 86677136, compound

Participants

Reaction Steps

To a cooled (−78° C.) solution of thiophene (10a) (3.18 g, 37.87 mmol) in THF (20.0 mL) was slowly added n-BuLi (15.15 mL, 2.5 M solution in hexane). After 30 minutes, a solution of (S)-(−)-propylene oxide (11a) (2.0 g, 34.43 mmol) in THF (10 mL) was added followed by BF3.Et2O (4.9 g, 34.43 mmol). The resulting solution was slowly brought to room temperature and stirred for over night. The reaction was quenched with NH4Cl solution (20 mL) and extracted with ether (3×50 mL). The organic extracts were dried and solvent was distilled off. The obtained crude product was dissolved in DCM (50 mL) and DIPEA (6.67 g, 51.6 mmol) and cooled to 0° C. A solution of methanesulfonyl chloride (10.0 g, 87.3 mmol) in DCM (4.93 g, 34.43 mmol) was added and resulting mixture was stirred at room temperature for over night. The reaction mixture was washed with water (3×30 mL), dried and concentrated to give crude compound that was purified on silica gel column using 20% EtOAc/hexane to afford (1S)-1-methyl-2-thien-2-ylethyl methanesulfonate (12a, 5.2 g, 68%) 1H NMR (CDCl3) δ 1.48 (d, 3H, J=6.0 Hz), 2.71 (s, 3H), 3.05-3.22 (m, 2H), 4.85-4.95 (m, 1H), 6.90-6.98 (m, 2H), 7.19 (d, 1H, J=3.0 Hz).

Provenance & Evidence