The base-catalysed Tamura cycloaddition reaction: calculation, mechanism, isolation of intermediates and asymmetric
Bruce Lockett-Walters1, Cristina Trujillo, Brendan Twamley
1School of Chemistry, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland. twamleyb@tcd.ie connons@tcd.ie trujillc@tcd.ie.
Abstract:
A combined experimental and computational investigation has revealed that the base-catalysed Tamura cycloaddition between homophthalic anhydride and activated alkenes/alkynes - a reaction previously thought of as a Diels-Alder type process - proceeds via a stepwise mechanism involving conjugate addition and ring closure; which allowed the first catalytic asymmetric α-substitution reactions to be demonstrated with up to >99% ee.
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