title: Asymmetric Sequential Cu-Catalyzed 1,6/1,4-Conjugate Additions of Hard Nucleophiles to Cyclic Dienones: Determination of Absolute Configurations and Origins of Enantioselectivity.
abstract: The first stereocontrolled Cu-catalyzed sequential 1,6/1,4-asymmetric conjugate addition (ACA) of C-metalated hard nucleophiles to cyclic dienones is reported. The use of DiPPAM (diphenylphosphinoazomethinylate) followed by a phosphoramidite as the stereoinducing ligands facilitated both high ee values for the 1,6-ACA and high de values for the 1,4-ACA reaction components, which thus gave enantioenriched 1,3-dialkylated moieties. The absolute configurations were determined by using vibrational circular dichroism (VCD) and optical rotatory dispersion (ORD) spectroscopy, in combination with DFT calculations and X-ray analysis. Interestingly, DFT calculations for the mechanism of enantioselective 1,6-addition by using an unprecedented Cu-Zn bimetallic catalytic system confirmed this attribution. Lastly, exploring intramolecular cyclization avenues for enantioenriched 1,3-dialkylated products provided access to the challenging drimane skeleton.
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, CNRS UMR 6226, 11 allée de Beaulieu, CS 50837, 35708, Rennes Cedex 7, France.
authors.forename: Charlie
authors.initials: C
authors.lastname: Blons
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, CNRS UMR 6226, 11 allée de Beaulieu, CS 50837, 35708, Rennes Cedex 7, France.
authors.forename: Marie S T
authors.initials: MST
authors.lastname: Morin
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, CNRS UMR 6226, 11 allée de Beaulieu, CS 50837, 35708, Rennes Cedex 7, France.
authors.forename: Thibault E
authors.initials: TE
authors.lastname: Schmid
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, CNRS UMR 6226, 11 allée de Beaulieu, CS 50837, 35708, Rennes Cedex 7, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Vives
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, CNRS UMR 6226, 11 allée de Beaulieu, CS 50837, 35708, Rennes Cedex 7, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Colombel-Rouen
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, CNRS UMR 6226, 11 allée de Beaulieu, CS 50837, 35708, Rennes Cedex 7, France.
authors.forename: Olivier
authors.identifier: http://orcid.org/0000-0002-4551-473X
authors.initials: O
authors.lastname: Baslé
authors.affiliation: Université de Rennes 1, CNRS, UMR 6226, Campus de Beaulieu, 35042, Rennes Cedex, France.
authors.forename: Thibault
authors.initials: T
authors.lastname: Reynaldo
authors.affiliation: Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA.
authors.forename: Cody L
authors.initials: CL
authors.lastname: Covington
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Chimie Théorique CC 137, 4, place Jussieu F., 75252, Paris Cedex 05, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Halbert
authors.affiliation: School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia.
authors.forename: Sean N
authors.initials: SN
authors.lastname: Cuskelly
authors.affiliation: School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia.
authors.forename: Paul V
authors.initials: PV
authors.lastname: Bernhardt
authors.affiliation: School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia.
authors.forename: Craig M
authors.identifier: http://orcid.org/0000-0002-3834-7398
authors.initials: CM
authors.lastname: Williams
authors.affiliation: Université de Rennes 1, CNRS, UMR 6226, Campus de Beaulieu, 35042, Rennes Cedex, France.
authors.forename: Jeanne
authors.identifier: http://orcid.org/0000-0002-4037-6067
authors.initials: J
authors.lastname: Crassous
authors.affiliation: Department of Chemistry, Vanderbilt University, Nashville, TN, 37235, USA.
authors.forename: Prasad L
authors.identifier: http://orcid.org/0000-0001-6458-0508
authors.initials: PL
authors.lastname: Polavarapu
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, CNRS UMR 6226, 11 allée de Beaulieu, CS 50837, 35708, Rennes Cedex 7, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Crévisy
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Chimie Théorique CC 137, 4, place Jussieu F., 75252, Paris Cedex 05, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Gérard
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, CNRS UMR 6226, 11 allée de Beaulieu, CS 50837, 35708, Rennes Cedex 7, France.
authors.forename: Marc
authors.identifier: http://orcid.org/0000-0002-7080-9708
authors.initials: M
authors.lastname: Mauduit
keywords: asymmetric catalysis; circular dichroism; configuration determination; conjugate addition; copper