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Updated: Jun 5, 2025

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Published on: May 26, 2019
Asymmetric isochalcogenourea-catalysed (4 + 2)-cycloadditions of ortho-quinone methides and allenoates
Anna Scheucher1, Christoph Gross2, Magdalena Piringer1
1Institute of Organic Chemistry, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz, Austria. mario.waser@jku.at.
Abstract:
Chiral isochalcogenoureas (i.e. isothioureas and isoselenoureas) catalyse the asymmetric (4 + 2)-cycloaddition of various allenoates with ortho-quinone methides. This approach provides straightforward access to different chromane derivatives with high enantioselectivities, good yields, and control of the configuration of the exocyclic double bond. Furthermore, some of the novel ortho-quinone methides used herein were successfully integrated into the Mayr reactivity scale by determining their electrophilicity parameter.
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