title: Kinetic resolution of unsaturated amides in a chlorocyclization reaction: concomitant enantiomer differentiation and face selective alkene chlorination by a single catalyst.
abstract: The first example of a kinetic resolution via chlorofunctionalization of olefins is reported. The enantiomers of racemic unsaturated amides were found to have different hydrogen-bonding affinities for chiral Lewis bases in numerous solvents. This interaction was exploited in developing a kinetic resolution of racemic unsaturated amides via halocyclization. The same catalyst serves to both "sense chirality" in the substrate as well as mediate a highly face-selective chlorine delivery onto the olefin functionality, resulting in stereotriad products in up to 99:1 dr and up to 98.5:1.5 er. The selectivity factors were typically greater than 50 to allow for the simultaneous synthesis of both the products and unreacted substrates in highly enantioenriched form at yields approaching 50%. The reaction employs catalytic amounts (≤0.50 mol %) of a commercially available and recyclable organocatalyst.
authors.affiliation: Department of Chemistry, Michigan State University , East Lansing, Michigan 48824, United States.
authors.forename: Arvind
authors.initials: A
authors.lastname: Jaganathan
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Staples
authors.forename: Babak
authors.initials: B
authors.lastname: Borhan
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D000577:Amides / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D054879:Halogenation; D007700:Kinetics; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D000577:Amides