Pentanidium–Catalyzed Enantioselective α-Hydroxylation of Oxindoles Using Molecular Oxygen

Yuanyong Yang, Farhana Moinodeen, Willy Chin, Ting Ma, Zhiyong Jiang and Choon-Hong Tan

Org. Lett.201214184762-4765

Abstract: Pentanidium-catalyzed α-hydroxylation of 3-substituted-2-oxindoles using molecular oxygen has been developed with good yields and enantioselectivities. This reaction does not require an additional reductant such as triethyl phosphite, which was typically added to reduce the peroxide intermediate. The reaction was demonstrated to consist of two-steps: an enantioselective formation of hydroperoxide oxindole and a kinetic resolution of the hydroperoxide oxindole via reduction with enolates generated from the oxindoles.

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