Iodine → 4-((1R,2S)-2-(tert-butyldimethylsilyloxy)-1-(5-(4-(tert-butyldimethylsilyloxy)phenyl)-1,3,4-oxadiazol-2-yl)propylamino)-2-chloro-3-methylbenzonitrile

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Reaction Steps

Dehydrative cyclization of 4-(tert-butyldimethylsilyloxy)-N′-((2R,3S)-3-(tert-butyldimethylsilyloxy)-2-(3-chloro-4-cyano-2-methylphenylamino)butanoyl)benzohydrazide (intermediate 8b) (453 mg, 0.72 mmol) with performed with polystyrene supported triphenylphosphine (PS-PPh3) (3.0 mmol/g, 575 mg, 1.72 mmol), I2 (435 mg, 1.71 mmol), and TEA (0.8 mL, 5.7 mmol) as described in the preparation of intermediate 7c. After column chromatography (30% EtOAc/hexanes) the title compound was isolated as a white solid (329 mg, 75%). 1H NMR (500 MHz, CDCl3, δ in ppm) 7.81 (AA′XX′, J=8.7 Hz, 2H), 7.32 (d, J=8.6 Hz, 1H), 6.91 (AA′XX′, J=8.8 Hz, 2H), 6.47 (d, J=8.7 Hz, 1H), 5.35 (d, J=8.7 Hz, 1H), 4.77 (m, 1H), 4.52 (m, 1H), 2.36 (s, 3H), 1.40 (d, J=6.2 Hz, 3H), 0.98 (s, 9H), 0.86 (s, 9H), 0.22 (s, 6H), 0.06 (s, 3H), −0.18 (s, 3H).

Provenance & Evidence