Methanol → 4-{[N-(6-{[Bis(methylethyl)amino](2-cyanoethoxy)phosphinooxy}hexyl)carbamoyl]methyl)-2-oxo-2H-chromen-7-yl 2,2-dimethylpropanoate

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Reaction Steps

To a solution of 33a (0.6 g, 1.5 mmol) in 10 mL of anhydrous CH2Cl2 was added triethylamine (0.4 mL) followed by 2-cyanoethyl diisopropylchlorophosphoramidite (0.35 mL, 1.6 mmol). The solution was kept at room temperature for 1 h and treated with 0.1 mL of MeOH. The solvent was evaporated and the residue was partitioned between ethyl acetate and saturated NaHCO3. The organic phase was washed with saturated NaCl, dried over Na2SO4 and concentrated. The crude product was chromatographed on silica eluting with 5% triethylamine in ethyl acetate. Concentration of the pure product fractions and drying under vacuum afforded 0.59 g (65%) of 34 as a colorless, viscous oil.

Provenance & Evidence