Abstract
A protocol for the highly enantioselective synthesis of 9-substituted tetrahydroxanthenones by means of asymmetric Brønsted acid catalysis has been developed. A chiral binolbased N-triflyphosphoramide was found to promote the in situ generation of ortho-quinone methides and their subsequent reaction with 1,3-cyclohexanedione to provide the desired products with excellent enantioselectivities. In addition, a highly enantio- and diastereoselective Brønsted acid catalyzed desymmetrization of 5-monosubstituted 1,3-dicarbonyl substrates with ortho-quinone methides gives rise to valuable tetrahydroxanthenes containing two distant stereocenters.
Original language | English (US) |
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Pages (from-to) | 13258-13263 |
Number of pages | 6 |
Journal | Angewandte Chemie - International Edition |
Volume | 53 |
Issue number | 48 |
DOIs | |
State | Published - Nov 24 2014 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Keywords
- Cyclization
- Enantioselectivity
- Heterocycles
- Organocatalysis
- Synthetic methods
ASJC Scopus subject areas
- Catalysis
- General Chemistry