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Highly Enantioselective Inverse‐Electron‐Demand Hetero‐Diels–Alder Reactions of α,β‐Unsaturated Aldehydes
Author(s) -
Gademann Karl,
Chavez David E.,
Jacobsen Eric N.
Publication year - 2002
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 - 10.1002/1521-3773(20020816)41:16<3059::aid-anie3059>3.0.co;2-i
Subject(s) - enantioselective synthesis , yield (engineering) , chemistry , aryl , inverse , catalysis , alkyl , solvent , organic chemistry , medicinal chemistry , materials science , mathematics , geometry , metallurgy
Straightforward access to useful synthetic intermediates is provided by this new method. Simple, α , β ‐unsaturated aldehydes are excellent substrates in the hetero‐Diels–Alder reaction with inverse electron demand, catalyzed by Cr III –Schiff base complexes (see scheme; R 1 , R 2 =alkyl or aryl) in the presence of 4‐Å molecular sieves and no solvent. The resulting dihydropyrans are obtained in high enantio‐ (89–98 % ee ) and diastereoselectivity (>95 % de ) and yield (40–95 %).