Triphenylphosphine → Benzyl (S)-2-(8,9-dihydro-9-methyl-7H-[1,4]oxazino[2,3-g]indazol-1-yl)-1-methylethylcarbamate

Participants

Reaction Steps

To a stirred solution of the product from Step B (0.36 g, 0.82 mmol) in tetrahydrofuran (10 mL) at 0° C. was added triphenylphospine (0.26 g, 0.98 mmol) followed by diethyl azodicarboxylate (0.23 mL, 1.23 mmol). After 2 h, a saturated aqueous solution of ammonium chloride (30 mL) was added and the mixture was extracted with ethyl acetate (3×65 mL). The combined extracts were washed with brine (10 mL), dried (MgSO4), and evaporated to a residue which was purified by chromatography (silica, 30%-50% ethyl acetate in hexane) to give an oil (0.28 g, 89%): 1H NMR (CDCl3) δ 7.88 (1H, s), 7.30 (6H, m), 6.73 (1H, d, J=8.4 Hz), 4.91 (2H, s), 4.63 (2H, m), 4.37 (2H, m), 4.09 (1H, m), 3.26 (2H, m), 2.73 (3H, s), 1.06 (3H, d, J=6.4 Hz); MS (ES) m/z 381 (M+).

Provenance & Evidence