Enantioselective α-Hydroxylation by Modified Salen-Zirconium(IV)-Catalyzed Oxidation of β-Keto Esters.
Title | Enantioselective α-Hydroxylation by Modified Salen-Zirconium(IV)-Catalyzed Oxidation of β-Keto Esters. |
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Authors | Yang, F.; Zhao, J.; Tang, X.; Zhou, G.; Song, W.; Meng, Q. |
Journal | Org Lett |
DOI | 10.1021/acs.orglett.6b03554 |
Abstract |
The highly enantioselective α-hydroxylation of β-keto esters using cumene hydroperoxide (CHP) as the oxidant was realized by a chiral (1S,2S)-cyclohexanediamine backbone salen-zirconium(IV) complex as the catalyst. A variety of corresponding chiral α-hydroxy β-keto esters were obtained in excellent yields (up to 99%) and enantioselectivities (up to 98% ee). The zirconium-catalyzed enantioselective α-hydroxylation of β-keto esters was scalable, and the zirconium catalyst was recyclable. The reaction can be performed in gram scale, and corresponding chiral products were acquired in 95% yield and 99% ee. |