title: Diastereoselective Conjugate Addition to (+)-Camphorsulfonic Acid Derived Nitroalkenes: Synthesis of alpha-Hydroxy and alpha-Amino Acids.
abstract: Diastereoselective tandem conjugate addition of both oxygen- and nitrogen-centered nucleophiles to the novel (1S)-10-camphorsulfonic acid derived nitroalkenes 9, 10, and 11 and ozonolysis gave the alpha-hydroxy and alpha-amino thiol acid derivatives 12, 13, and 14. In all cases, the (R)-diastereomer was formed as the major component albeit with only modest levels of selectivity (33-71% de). The structures of the products and the stereochemistry of the Michael addition step were unequivocally established by X-ray crystallographic studies of nitroalkenes 9 and 10 and (2S)-12c and (2R)-13a and by alternative syntheses from (S)-alanine, (S)-valine, and ethyl (S)-lactate.
authors.affiliation: Department of Chemistry, Imperial College, South Kensington, London, SW7 2AY, UK and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208.
authors.forename: Anthony G. M.
authors.initials: AG
authors.lastname: Barrett
authors.forename: D. Christopher
authors.initials: DC
authors.lastname: Braddock
authors.forename: Paul W. N.
authors.initials: PW
authors.lastname: Christian
authors.forename: Daniel
authors.initials: D
authors.lastname: Pilipauskas
authors.forename: Andrew J. P.
authors.initials: AJ
authors.lastname: White
authors.forename: David J.
authors.initials: DJ
authors.lastname: Williams