Synergistic Rhodium/Phosphoric Acid Catalysis for the Enantioselective Addition of Oxonium Ylides to ortho‐Quinone Methides |
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Authors: | Dr Santosh Kumar Alamsetti M?Sc Matthias Spanka Prof?Dr Christoph Schneider |
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Institution: | Institut für Organische Chemie, Universit?t Leipzig, Leipzig, Germany |
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Abstract: | We report herein a powerful and highly stereoselective protocol for the domino‐type reaction of diazoesters with ortho‐quinone methides generated in situ to furnish densely functionalized chromans with three contiguous stereogenic centers. A transition‐metal and a Brønsted acid catalyst were shown to act synergistically to produce a transient oxonium ylide and ortho‐quinone methide, respectively, in two distinct cycles. These intermediates underwent subsequent coupling in a conjugate‐addition–hemiacetalization event in generally good yield with excellent diastereo‐ and enantioselectivity. |
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Keywords: | ortho-quinone methides oxonium ylides phosphoric acids rhodium synergistic catalysis |
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