title: A redox-reconfigurable, ambidextrous asymmetric catalyst.
abstract: A redox-reconfigurable catalyst derived from L-methionine and incorporating catalytic urea groups has been synthesized. This copper complex catalyzes the enantioselective addition of diethyl malonate to trans-β-nitrostyrene. Either enantiomer of the product can be predetermined by selection of the oxidation state of the copper ion. Enantiomeric excesses of up to 72% (S) and 70% (R) were obtained in acetonitrile. The ability of the catalyst to invert enantiomeric preference was reproduced with several different solvents and bases. Facile interconversion between the Cu(2+) and Cu(+) redox states allowed easy access to both active helical forms of the complex and, therefore, dial-in enantioselectivity.
authors.affiliation: Department of Chemistry, New York University, New York, New York 10003, United States.
authors.forename: Shahab
authors.initials: S
authors.lastname: Mortezaei
authors.forename: Noelle R
authors.initials: NR
authors.lastname: Catarineu
authors.forename: James W
authors.initials: JW
authors.lastname: Canary