2-Butene, 1-bromo- → Methyl 3-[3-t-butylthio-1-(4-chlorobenzyl)-4-crotyl-5-hydroxyindol-2-yl]-2,2-dimethylpropanoate

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Reaction Steps

To a suspension of KH (35% dispersion in oil, 547 mg, 4.78 mmol) in p-xylene (20 mL) there was added methyl 3-[3-tert-butylthio-1-(4-chlorobenzyl)-5-hydroxyindol-2-yl]-2,2-dimethylpropanoate from Example 1, Method A, Step 3 (2.0 g, 4.35 mmol) and the mixture was refluxed for 20 minutes; after cooling, there was added freshly fused ZnCl2 (68 mg, 0.5 mmol) and the mixture was again refluxed for one hour, then cooled down to r.t. To the solution was added crotyl bromide (882 mg, 6.53 mmol) and stirring was continued at room temperature overnight. The mixture was quenched with saturated aqueous NH4Cl (20 mL) and 2 mL of 1N HCl. The organic phase was collected and the aqueous phase extracted with EtOAc. The combined organic phases were washed with H2O 3 times, dried and evaporated. The residue was chromatographed to afford the title compound as the minor component, as a yellow oil.

Provenance & Evidence