Indole → 1-(2,2-dimethyl-1,3-dioxolan-4-ylmethyl)-1H-indole

Participants

Reaction Steps

To a stirred room temperature solution of indole (5.9 g, 50 mmol) in THF (100 mL) was added sodium hydride (2.4 g of 60% in mineral oil, 60 mmol) in one portion. After 30 minutes, 4-chloromethyl-2,2-dimethyl-1,3-dioxolane (10.6 mL, 75 mmol) was added followed by tetra-n-butylammonium iodide (1.9 g, 5 mmol) and the mixture was warmed at reflux. After 24 hours, LCMS showed about 50% conversion [MS m/z 232 (MH+)]. Additional 4-chloromethyl-2,2-dimethyl-1,3-dioxolane (11.4 mL) was added and the refluxing continued. After 18 hours, the mixture was cooled, diluted with THF (300 mL), filtered, and concentrated in vacuo to afford a brown oil. The residue was purified by column chromatography over silica gel eluting with 0-100% methylene chloride in hexanes and the product-rich fractions were collected to afford 3.3 g of 1-(2,2-dimethyl-1,3-dioxolan-4-ylmethyl)-1H-indole as a brownish oil.

Provenance & Evidence