2-Methyl-2-butene → 6-Methoxy-2-(methoxycarbonyl)-1-(pyridin-2-ylmethyl)-1H-indole-3-carboxylic Acid

Participants

Reaction Steps

General Procedure K. To a suspension of methyl3-formyl-6-methoxy-1-(pyridin-2-ylmethyl)-1H-indole-2-carboxylate (Compound 91, 1.64 g, 5.07 mmol) in t-BuOH (120 ml) and dioxane (20 ml) was added 2-methyl-2-butene (25 ml) and a solution of NaH2PO4 (7.3 g, 61 mmol) and NaClO2 (80%, 5.7 g, 50.7 mmol) in H2O (100 ml). The reaction was stirred at room temperature for 6 h, extracted with EtOAc (×2). The combined organic layer was washed with brine, dried over Na2SO4, and concentrated in vacuo. The residue was purified by chromatography on silica gel (0→100% EtOAc-hexanes) to yield the title compound as an off-white solid.

Provenance & Evidence