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Amino Acid Esters as Chiral Auxiliary Groups in Lewis Acid Catalyzed Reactions of Electron‐rich Siloxydienes with Imines
Author(s) -
Waldmann Herbert,
Braun Matthias,
Dräger Martin
Publication year - 1990
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199014681
Subject(s) - chemistry , lewis acids and bases , diastereomer , aminal , diene , curtius rearrangement , chiral auxiliary , hydrolysis , cleavage (geology) , catalysis , organic chemistry , chiral lewis acid , mannich reaction , amino acid , medicinal chemistry , stereochemistry , enantioselective synthesis , biochemistry , geotechnical engineering , natural rubber , fracture (geology) , engineering
In the presence of various Lewis acids, the amino acid ester‐imines 1 undergo tandem Mannich‐Michael reactions and aza‐Diels‐Alder reactions respectively with the Danishefsky diene 2 and the Brassard diene 3 . The products are formed in good yields and high diastereomeric excesses. Cleavage of the chiral auxiliary group—achieved by means of a Curtius rearrangement, by which the α‐C of the amino acid is converted into an aminal—and subsequent hydrolysis afforded unsaturated lactams such as 4 and enaminones 5 , which find use as synthetic building blocks.