Zirconium-Salan Catalyzed Enantioselective α-Hydroxylation of β-Keto Esters
- 주제(키워드) Asymmetric catalysis , Hydroxylation , Indoxacarb , Oxidation , Zirconium
- 등재 SCIE, SCOPUS
- 발행기관 Wiley-VCH Verlag
- 발행년도 2020
- 총서유형 Journal
- URI http://www.dcollection.net/handler/ewha/000000169490
- 본문언어 영어
- Published As https://dx.doi.org/10.1002/adsc.202000290
- 저작권 이화여자대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
We report herein the development of enantioselective and scalable α-hydroxylation of 1-indanone-derived β-keto esters by Zr(IV) complexes bearing readily available C2-symmetric salan ligands and cumene hydroperoxide as an oxidant, affording synthetically valuable hydroxylation products in high yields (up to 99%) with excellent enantioselectivities (up to 99% ee) under mild reaction conditions. In mechanistic studies, we have shown that (1) a Zr(IV)-salan complex was generated in situ as the active catalyst responsible for the chiral induction, (2) the transfer of the electrophilic fragment from cumene hydroperoxide to the Zr(IV)-bound enolate was accompanied by a heterolytic O−O bond cleavage, and (3) the formation of hydrogen bond between the amine hydrogen atom(s) of the salan ligand and the hydroxy group of cumene hydroperoxide was significant for stabilizing the stereocontrolled transition state and improving the enantioselectivity. (Figure presented.). © 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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