Tetrabutylammonium Fluoride → HCID 58468011, compound

Participants

Reaction Steps

In a 100 mL round-bottom flask was dissolved (9R)-6-(2,3-difluorophenyl)-9-(triisopropylsilyloxy)-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridin-5-ol (mixture of intermediates 2 and 3, 224.3 mg, 0.501 mmol) in tetrahydrofuran (4 mL) to give a colorless solution. TBAF (0.752 mL, 0.752 mmol) was added, and the mixture was stirred at room temperature for 2 h. LCMS indicated complete conversion of major component while the minor one did not change. Tetrahydrofuran was removed in vacuo and the residue was partitioned between water and ethyl acetate. The layers were separated and the aqueous layer was extracted with ethyl acetate. The combined organic layer was washed with brine, dried with Sodium sulfate, and concentrated to give a tan oil. FCC up to 50% ethyl acetate/hexane afforded intermediate 3 unchanged (38 mg, 17%) as a white crystalline solid, and intermediate 4 (95 mg, 65%) as a colorless oil (solidified upon standing). Intermediate 4 was further crystallized and single crystals were obtained. Its relative stereochemistry was proven by x-ray studies.

Provenance & Evidence