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Intramolecular Aza‐Diels–Alder Reactions of ortho ‐Quinone Methide Imines: Rapid, Catalytic, and Enantioselective Assembly of Benzannulated Quinolizidines
Author(s) -
Kretzschmar Martin,
Hofmann Fabian,
Moock Daniel,
Schneider Christoph
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201800787
Subject(s) - quinone methide , enantioselective synthesis , intramolecular force , chemistry , imine , substituent , stereochemistry , quinone , organic chemistry , catalysis
Aza‐Diels–Alder reactions (ADARs) are powerful processes that furnish N‐heterocycles in a straightforward fashion. Intramolecular variants offer the additional possibility of generating bi‐ and polycyclic systems with high stereoselectivity. We report herein a novel Brønsted acid catalyzed process in which ortho ‐quinone methide imines tethered to the dienophile via the N substituent react in an intramolecular ADAR to form complex quinolizidines and oxazinoquinolines in a one‐step process. The reactions proceed under very mild conditions, with very good yields and good to very good diastereo‐ and enantioselectivities. Furthermore, the process was extended to a domino reaction that efficiently combines substrate synthesis, ortho ‐quinone methide imine formation, and ADAR.