title: Design and Synthesis of Novel Chiral Dirhodium(II) Carboxylate Complexes for Asymmetric Cyclopropanation Reactions.
abstract: A novel approach to the design of dirhodium(II) tetracarboxylates derived from (S)-amino acid ligands is reported. The approach is founded on tailoring the steric influences of the overall catalyst structure by reducing the local symmetry of the ligand's N-heterocyclic tether. The application of the new approach has led to the uncovering of [Rh2(S-tertPTTL)4] as a new member of the dirhodium(II) family with extraordinary selectivity in cyclopropanation reactions. The stereoselectivity of [Rh2(S-tertPTTL)4] was found to be comparable to that of [Rh2(S-PTAD)4] (up to >99 % ee), with the extra benefit of being more synthetically accessible. Correlations based on X-ray structures to justify the observed enantioinduction are also discussed.
authors.affiliation: University of Canberra, ACT, 2601, Australia.
authors.forename: Frady G
authors.identifier: http://orcid.org/0000-0002-7279-276X
authors.initials: FG
authors.lastname: Adly
authors.affiliation: School of Physical Sciences, Chemistry, University of Tasmania, Hobart, TAS, 7001, Australia.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Gardiner
authors.affiliation: Biomedical science department, University of Canberra, ACT, 2601, Australia. ashraf.ghanem@canberra.edu.au.
authors.forename: Ashraf
authors.identifier: http://orcid.org/0000-0001-9205-349X
authors.initials: A
authors.lastname: Ghanem
keywords: asymmetric synthesis; carbenoids; chiral catalysis; cyclopropanation; rhodium