title: Highly enantioselective catalytic asymmetric [2+2] cycloadditions of cyclic α-alkylidene β-oxo imides with ynamides.
abstract: Highly enantioselective catalytic asymmetric [2+2] cycloadditions of cyclic α-alkylidene β-oxo imides with ynamides are described. The high reactivity of the cyclic α-alkylidene β-oxo imide allows the [2+2] cycloadditions of a hindered substrate with unreactive ynamides at low temperature. The X-ray crystallographic analysis of the product suggests that the enantioselectivity of the [2+2] cycloaddition can be well explained by the chelate model comprising the intramolecular hydrogen bond, wherein the cyclic α-alkylidene β-oxo imide coordinates with Cu(II) through the two imide carbonyls. The imide group in the product can be transformed to amide, nitrile, and ester groups; moreover, it is removable.
authors.affiliation: Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555 (Japan), Fax: (+81) 3-5286-3240, Home page: http://www.chem.waseda.ac.jp/nakada/
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Enomoto
authors.forename: Harufumi
authors.initials: H
authors.lastname: Oyama
authors.forename: Masahisa
authors.initials: M
authors.lastname: Nakada
mesh_terms: D002384:Catalysis; D061565:Cycloaddition Reaction; D007094:Imides / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D007094:Imides
keywords: asymmetric catalysis; cycloadditions; enantioselectivity; imides; ynamides