title: Dynamic resolution of 2-cyclohexylidene acetaldehydes through organocatalytic dienamine [4+2] cycloaddition.
abstract: Organocatalytic formed dienamines are shown to be involved in dynamic resolution of 2-cyclohexylidene acetaldehydes. By reaction of racemic 2-cyclohexylidene acetaldehydes with benzoquinones in the presence of a diarylprolinol-silyl ether catalyst, tricyclic products are formed in good to high yield and excellent enantioselectivity, while the diastereoselectivity depends on the substituent in the 2-cyclohexylidene acetaldehydes. Studies based on experimental observations and DFT-calculations point to a dynamic thermodynamic resolution-directed pathway. Some transformations of the optically active products are also presented.
authors.affiliation: Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark. kaj@chem.au.dk.
authors.forename: Jakob
authors.initials: J
authors.lastname: Blom
authors.forename: Tore Kiilerich
authors.initials: TK
authors.lastname: Johansen
authors.forename: Frank
authors.initials: F
authors.lastname: Jensen
authors.forename: Karl Anker
authors.initials: KA
authors.lastname: Jørgensen