One-Pot Synthesis of Highly Functionalized Oxindoles under Swern Oxidation Conditions

The reaction of indole derivatives bearing a 3- or 4-hydroxyalkyl chain with dimethyl sulfoxide and oxalyl chloride under Swern conditions led to a one-pot process involving three different synthetic transformations, namely oxidation of indole to oxindole, introduction of a chlorine substituent at the oxindole C-3 position, and substitution of the hydroxyl group in the side chain by chlorine. In spite of its mechanistic complexity, this synthetically useful process proceeded in good to excellent overall yield.