Acetone → HCID 10495806, compound

Participants

Reaction Conditions

Reaction Steps

To a cold (-78° C.) solution of 1-(8-tert-butyl-4,4-dimethyl-2,3-dihydrobenzopyran-6-yl)1-ethanone (0.35 g, 1.36 mmol) in CH2Cl2 (3.0 mL) is added TMSOTf (0.32 mL, 1.63 mmol, 1.2 equiv) and (i-Pr)2NEt (0.28 mL, 1.63 mmol, 1.2 equiv) dropwise. The resulting red mixture is stirred at -78° C. for 30 min, and then allowed to warm to room temperature over 1 h. The resulting pale red solution is recooled to -78° C. and acetone (0.12 mL, 1.63 mmol, 1.2 equiv) and TiCl4 (0.15 mL, 1.36 mmol, 1.0 equiv) are added dropwise. The resulting deep red solution is allowed to warm to room temperature over 3.5 h and 0.5N HCl is added and the mixture is stirred for 30 min. The reaction mixture is diluted with hexanes and washed with water and brine. The aqueous layers are extracted with hexanes; the combined organic layers are dried (MgSO4), filtered and concentrated. The residue is purified by flash column chromatography on silica (hexanes, hexanes/EtOAc; 10/1) to give the title compound (0.30 g, 70%) as a pale yellow solid which is recrystallized using pentane.

Provenance & Evidence