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Synergistic Rhodium/Phosphoric Acid Catalysis for the Enantioselective Addition of Oxonium Ylides to ortho ‐Quinone Methides
Author(s) -
Alamsetti Santosh Kumar,
Spanka Matthias,
Schneider Christoph
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201509247
Subject(s) - oxonium ion , chemistry , stereocenter , enantioselective synthesis , rhodium , ylide , phosphoric acid , brønsted–lowry acid–base theory , catalysis , combinatorial chemistry , medicinal chemistry , organic chemistry , ion
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.