Oxazaborolidinone-catalyzed enantioselective Diels-Alder reaction of acyclic alpha,beta-unsaturated ketones.
allo-Threonine-derived O-acyl-B-phenyl-oxazaborolidinones are demonstrated to be powerful and highly enantioselective Lewis acid catalysts for the Diels-Alder reaction of simple acyclic enone dienophiles, expanding the scope of ketone dienophiles and dienes. With 10 to 20 mol % of catalyst, the Diels-Alder adducts are obtained in 76-98% ee with high endo-selectivity. The catalyst exhibits high activity for the reaction with the less reactive beta-substituted dienophiles and the less reactive 1,3-cycohexadiene and 1,3-butadiene derivatives. The application of the catalysts to the Diels-Alder reaction of furan is also described.
Singh
Ram Shanker
RS
Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
Adachi
Shinya
S
Tanaka
Fumi
F
Yamauchi
Toyonao
T
Inui
Chieko
C
Harada
Toshiro
T
D001880:Boranes; D002384:Catalysis; D003500:Cyclization; D006573:Heterocyclic Compounds, 1-Ring / Q000737:chemistry*; D007659:Ketones / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
D001880:Boranes; D006573:Heterocyclic Compounds, 1-Ring; D007659:Ketones; C527334:oxazaborolidinone