18-Crown-6 → (+/-)-tert-Butyl 4-(1-(5-cyanobenzo[d]oxazol-2-yl)-3-methoxy-3-oxopropyl)-5-methoxy-7-methyl-1H-indole-1-carboxylate

Participants

Reaction Steps

To a mixture of potassium tert-butoxide (108 mg, 0.958 mmol) in THF (0.715 mL) at −78° C. under nitrogen was added tert-butyl 4-((5-cyanobenzo[d]oxazol-2-yl)methyl)-5-methoxy-7-methyl-1H-indole-1-carboxylate (Example 144-A) (200 mg, 0.479 mmol) in THF (4.3 mL) under nitrogen. After stirring for 15 min a solution of 18-crown-6 (12.66 mg, 0.048 mmol) in THF (1.430 mL) was added to the mixture at the same temperature and stirred for another 15 min. Then a solution of methyl bromoacetate (0.618 mL, 6.71 mmol) in THF (0.715 mL) was degassed and added dropwise and stirred at the same temp for 10 min. The reaction mixture was quenched with a saturated solution of ammonium chloride, extracted with EtOAc (2×), passed through a phase separator and concentrated to give the title compound. MS (ESI+) m/z 490.32 (M+H).

Provenance & Evidence