Synthesis
DOI: 10.1055/a-2616-1628
Paper

Hydrogen-Bonding Cyclodiphosphazane Organocatalysts in Enantioselective Michael Additions

1   Department of Chemistry, Institut of Organic Chemistry, University of Cologne, Cologne, Germany
,
Xiaochen Wang
1   Department of Chemistry, Institut of Organic Chemistry, University of Cologne, Cologne, Germany
,
Denis Sartakov
1   Department of Chemistry, Institut of Organic Chemistry, University of Cologne, Cologne, Germany
› Author Affiliations

Supported by: DFG GO-930-13-1
Funding Information This project was funded by the Deutsche Forschungsgemeinschaft (DFG), GO-930-13-1.


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Dedication

Dedicated to Prof. Dr. Paul Knochel on the occasion of his 70th birthday.

Abstract

Chiral aryl-(1R,2R)-N,N-dimethyldiamino-cyclohexane (DMDACH)-substituted cyclodiphosphazanes are demonstrated to be efficient bifunctional hydrogen-bonding organocatalysts for the enantioselective Michael additions of 2-hydroxy-1,4-naphthoquinone (<90% ee), Meldrum’s acid (<55% ee), and kojic acid chloride (<80% ee) to β-nitrostyrene. The parent, unsubstituted phenyl-cyclodiphosphazane with PO functions shows superior enantioselectivity in most cases and even exceeds, with 55% ee, the enantioselectivity of Takemoto’s thiourea catalyst for the challenging Meldrum’s acid substrate (46% ee). For Michael additions of kojic acid chloride, the meta-CH3-substituted cyclodiphosphazane with PS functions is the most enantioselective (< 80% ee) catalyst. This highlights the benefits of modular cyclodiphosphazane structures, which can be tailored for specific substrates.

Supplementary Material



Publication History

Received: 04 April 2025

Accepted after revision: 15 May 2025

Article published online:
24 July 2025

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