18-Crown-6 → Tert-butyl 3-((5-cyclopropyl-3-(2-(trifluoromethoxy)phenyl)isoxazol-4-yl)methoxy)-8-azabicyclo[3.2.1]octane-8-carboxylate

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Reaction Steps

A 250-mL flask was purged with nitrogen and then charged with N-Boc-nortropine (2.9 g, 12.8 mmol), 18-Crown-6 (3.4 g, 12.8 mmol), and anhydrous tetrahydrofuran (80 mL). Potassium tert-butoxide (2.9 g, 25.6 mmol) was added in small portions, and the mixture was stirred vigorously under nitrogen fo(1 h. 4-(bromomethyl)-5-cyclopropyl-3-(2-(trifluoromethoxy)-phenyl)isoxazole (4.18 g, 11.6 mmol) was dissolved in anhydrous tetrahydrofuran (20 mL) and added dropwise, and the reaction mixture was stirred overnight under a positive nitrogen pressure. The solvent was removed in vacuo and the mixture diluted with water (100 mL) and ethyl acetate (100 mL). The organic layer was separated, dried with anhydrous MgSO4, and evaporated in vacuo. The crude residue was purified by silica gel chromatography using a gradient of 0-100% ethyl acetate/hexanes to yield the desired product as yellow oil. MS m/z 509.2 (M+1).

Provenance & Evidence