title: Asymmetric organocatalysis of 4 + 3 cycloaddition reactions.
abstract: Treatment of several 4-trialkylsilyloxypentadienals with a chiral secondary amine, trifluoroacetic acid, and a diene resulted in the formation of 4 + 3 cycloaddition products, which were enantiomerically enriched. This represents the first examples of the asymmetric organocatalysis of the 4 + 3 cycloaddition reaction. 2,5-Dimethylfuran reacted with 4-trimethylsilyloxy-2,4-pentadienal in the presence of catalytic amounts of chiral amine and acid to afford a cycloadduct in 64% yield as a single diastereomer with an enantiomeric excess of 89%.
authors.affiliation: Department of Chemistry, University of Missouri-Columbia, Columbia, Missouri 65211, USA. harmatam@missouri.edu
authors.forename: Michael
authors.initials: M
authors.lastname: Harmata
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Ghosh
authors.forename: Xuechuan
authors.initials: X
authors.lastname: Hong
authors.forename: Sumrit
authors.initials: S
authors.lastname: Wacharasindhu
authors.forename: Patrick
authors.initials: P
authors.lastname: Kirchhoefer