Isothiourea-catalysed enantioselective Michael addition of N-heterocyclic pronucleophiles to α,β-unsaturated aryl esters
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The isothiourea-catalysed enantioselective Michael addition of 3-aryloxindole and 4-substituted-dihydropyrazol-3-one pronucleophiles to α,β-unsaturated p-nitrophenyl esters is reported. This process generates products containing two contiguous stereocentres, one quaternary, in good yields and excellent enantioselectivities (>30 examples, up to > 95 : 5 dr and 99 : 1 er). This protocol harnesses the multifunctional ability of p-nitrophenoxide to promote effective catalysis. In contrast to previous methodologies using tertiary amine Lewis bases, in which the pronucleophile was used as the solvent, this work allows bespoke pronucleophiles to be used in stoichiometric quantities.
Shu , C , Liu , H , Slawin , A , Carpenter-Warren , C L & Smith , A D 2019 , ' Isothiourea-catalysed enantioselective Michael addition of N-heterocyclic pronucleophiles to α,β-unsaturated aryl esters ' , Chemical Science , vol. Advance Article . https://doi.org/10.1039/C9SC04303A
Copyright © 2019 The Author(s). Open Access Article. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
DescriptionThe research leading to these results (C. S., H. L.) has received funding from the Royal Society Newton Fellowship Programme. A.D.S. thanks the Royal Society for a Wolfson Research Merit Award.
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