Pyridine N-Oxide → Benzopyran

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

26.2 mg of compound [IV-1] (0.10 mmol) and 2.6 mg of the compound [Ia -1] (2.5 μmol) were dissolved in 1.25 mL of an acetonitrile solution of pyridine-N-oxide (0.02 M, 0.025 mmol), followed by cooling to 0° C. To the resulting solution was added 44.0 mg of iodosylbenzene (0.20 mmol) all at once under a nitrogen atmosphere, followed by stirring at 0° C. for twenty four hours. Insoluble matters were filtered out through Celite, the filtrate was concentrated, and the residues were purified by silica gel column chromatography (eluent: hexane-ethyl acetate=8:2-4:6) to obtain the intended compound. (epoxide yield: 20.1 mg (72%)) (asymmetric yield: 98% e.e.) (Daicel Chiralcel OJ, hexane-isopropanol=1:1, flow rate: 0.5 mL/min.)

Herkunft & Nachweise