Metaperiodic acid → 4-Allyl-5-methyl-3-styryl-1,3,4,5-tetrahydro-benzo[e][1,4]diazepin-2-one

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Reaction Steps

The product of Example 14 (117 mg, 0.4 mmol) was placed in a 25 mL round bottom flask and dissolved in methanol (2 mL) and water (1 mL). To this solution was added periodic acid (192 mg, 0.84 mmol), and the mixture was allowed to stir at room temperature for 2 hours. After this time, the solvent was then evaporated and the resulting residue was taken up in ethyl acetate (20 mL) and transferred to a separatory funnel. The organic layer was then washed with a saturated sodium bicarbonate solution (5×15 mL) until the aqueous layer no longer turned pink in color. The organic layer was then washed with brine (1×15 mL), dried over magnesium sulfate, filtered and evaporated. This resulting aminol was then dissolved in acetonitrile (4 mL) and to this solution was added (E)-2-Phenylvinylboronic acid (75 mg, 0.5 mmol), and the solution was brought to reflux for 4 hours. After this time, the reaction was diluted with ethyl acetate (40 mL), and transferred to a separatory funnel. The organic layer was washed with 1N NaOH (3×15 mL), brine (1×15 mL), dried over magnesium sulfate, filtered, and evaporated to yield the desired product, and an isomeric by-product in a combined yield of 81%. 1H NMR was used to estimate the ratio of product to by-product to be approximately 77:23. This mixture was taken crude to the next transformation to avoid further isomerization upon isolation. 1H NMR (250 MHz, CDCl3, major isomer) δ 7.75 (bs, 1H), 7.43-7.37 (m, 2H), 7.33-7.15 (m, 6H), 7.11-7.04 (m, 1H), 6.85-6.82 (m, 1H), 6.57 (dd, J=16.0 Hz, J=4.8 Hz, 1H), 5.92-5.69 (m, 1H), 5.18-5.03 (m, 2H), 4.44-4.39 (m, 1H), 4.29 (q, J=6.6 Hz, 1H), 3.27-3.16 (m, 1H), 2.92-2.80 (m, 1H), 1.55 (d, J=6.6 Hz, 3H).

Provenance & Evidence