Enantioselective NHC-catalysed redox [4+2]-hetero-Diels-Alder reactions using α-aroyloxyaldehydes and unsaturated ketoesters
Date
15/02/2017Grant ID
N/A
WM140071
Metadata
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Abstract
N-Heterocyclic carbene (NHC)-catalysed redox [4+2]-hetero-Diels-Alder reactions of α-aroyloxyaldehydes with either β,γ-unsaturated α-ketoesters or α,β-unsaturated γ-ketoesters generates substituted syn-dihydropyranones in good yield with excellent enantioselectivity (up to >99:1 er). The product diastereoselectivity is markedly dependent upon the nature of the unsaturated enone substituent. The presence of either electron-neutral or electron-rich aryl substituents gives excellent diastereoselectivity (up to >99:5 dr), while electron-deficient aryl substituents give reduced diastereoselectivity. In these cases, the syn-dihydropyranone products are more susceptible to base-promoted epimerisation at the C(4)-position under the reaction conditions, accounting for the lower diastereoselectivity obtained.
Citation
Taylor , J E , Davies , A T , Douglas , J J , Churchill , G & Smith , A D 2017 , ' Enantioselective NHC-catalysed redox [4+2]-hetero-Diels-Alder reactions using α-aroyloxyaldehydes and unsaturated ketoesters ' , Tetrahedron: Asymmetry , vol. 28 , no. 2 , pp. 355-366 . https://doi.org/10.1016/j.tetasy.2017.01.002
Publication
Tetrahedron: Asymmetry
Status
Peer reviewed
ISSN
0957-4166Type
Journal article
Rights
© 2017 Published by Elsevier Ltd. This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at: https://doi.org/10.1016/j.tetasy.2017.01.002
Description
The authors thank the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013) ERC Grant Agreement No. 279850 (J.E.T. and A.T.D.) as well as the EPSRC, UK and AstraZeneca plc, UK (Case award to J.J.D.) for financial support. A.D.S. thanks the Royal Society, London, UK, for a Wolfson Merit Award.Collections
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