Synlett 2013; 24(10): 1165-1169
DOI: 10.1055/s-0033-1338745
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© Georg Thieme Verlag Stuttgart · New York

Kinetic Resolution of 3-Hydroxy-3-Substituted Oxindoles through NHC-Catalyzed Oxidative Esterification

Shenci Lu
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Republic of Singapore   Fax: +65(677)91691   Email: zhaoyu@nus.edu.sg
,
Si Bei Poh
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Republic of Singapore   Fax: +65(677)91691   Email: zhaoyu@nus.edu.sg
,
Woon-Yew Siau
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Republic of Singapore   Fax: +65(677)91691   Email: zhaoyu@nus.edu.sg
,
Yu Zhao*
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Republic of Singapore   Fax: +65(677)91691   Email: zhaoyu@nus.edu.sg
› Author Affiliations
Further Information

Publication History

Received: 23 March 2013

Accepted: 15 April 2013

Publication Date:
08 May 2013 (online)


Abstract

The enantioselective synthesis of 3-hydroxy-3-substituted oxindoles has been extensively studied as they represent the core structure of a large number of natural products and pharmaceuticals. While the majority of previous methods focus on the asymmetric addition of different types of nucleophiles to the corresponding ketones, we have reported an unprecedented and alternative approach, namely catalytic kinetic resolution of this important class of tertiary alcohols to provide, for the first time, 3-hydroxy oxindoles with a wide range of 3-substituents including alkyl, alkenyl, alkynyl and aryl groups in highly enantioenriched form. The excellent level of differentiation of the two tertiary alcohol enantiomers (S up to 78) has been realized through oxidative esterification catalyzed by chiral N-heterocyclic carbene (NHC), with the aid of cooperative ­catalysis by Lewis acid.