title: Regioselective [2+2] and [4+2] cycloaddition reactivity in an asymmetric niobium(bisimido) moiety towards unsaturated organic molecules.
abstract: The asymmetric bis-imido structure and the lability of the diethyl ether linkage in complex 1 provide a niobium complex that undergoes regioselective [4+2] cycloaddition reactions with an α,β-unsaturated ketone and cycloaddition reactions that involve bond formation to the MAD ligand (MonoAzabutaDiene). DFT calculations have been used to support an initial azametallacyclobutene intermediate in the alkyne reaction.
authors.affiliation: Department of Chemistry, University of California, Berkeley, CA 94720-1460, USA. arnold@berkeley.edu.
authors.forename: A H
authors.initials: AH
authors.lastname: Obenhuber
authors.forename: T L
authors.initials: TL
authors.lastname: Gianetti
authors.forename: R G
authors.initials: RG
authors.lastname: Bergman
authors.forename: J
authors.initials: J
authors.lastname: Arnold