title: Enantioselective direct aldol-type reaction of azlactone via protonation of vinyl ethers by a chiral Brønsted acid catalyst.
abstract: Highly enantio- and diastereoselective direct aldol-type reaction of azlactones with oxocarbenium ions generated by protonation of vinyl ethers using a chiral phosphoric acid catalyst is presented. The method provides efficient access to biologically and pharmaceutically intriguing beta-hydroxy-alpha-amino acid derivatives having a quaternary stereogenic center at the alpha-carbon atom.
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan. mterada@mail.tains.tohoku.ac.jp
authors.forename: Masahiro
authors.initials: M
authors.lastname: Terada
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Tanaka
authors.forename: Keiichi
authors.initials: K
authors.lastname: Sorimachi