Hydrogen Peroxide → HCID 25196998, compound

Participants

Reaction Steps

6-Fluoro-2,2-dimethyl-8-nitro-2H-1-benzopyran (0.23 g, 1.0 mmol) was added to a dichloromethane solution (3 mL) of the optically active titanium-salan complex (E) (24 mg, 0.020 mmol) (2.0 mol % to a substrate) at 20° C. 30% hydrogen peroxide aqueous solution (0.12 g, 1.1 mmol) was divided into three equal portions and, while stirring the reaction solution, the first addition was conducted at 20° C., and after 30 minutes, the second addition was conducted, and after 1 hour, the third addition was conducted. The time of the first addition of 30% hydrogen peroxide aqueous solution was defined as the reaction start time. After stirring the solution for 24 hours from the reaction start time at 20° C., a reaction solution sample was taken. The reaction conversion rate of the taken sample was analyzed with HPLC. The conversion rate to the compound (VII′) was 96% and an optical purity was 99% ee or more. Analytical conditions; Column name: CHIRALPAK AD-RH (three columns are serially connected), Eluent: acetonitrile/20 mM (pH8) phosphate buffer solution=6/4 (v/v), Flow rate: 0.5 mL/min, Column temperature: 40° C., Retention time: product of the reaction 17.3 min, enantiomer 16.8 min, Measured wavelength: 220 nm.

Provenance & Evidence