title: The reactivities of iminoboranes with carbenes: BN isosteres of carbene-alkyne adducts.
abstract: The first examples of adducts of cyclic alkyl(amino) carbenes (CAAC) and N-heterocyclic carbenes (NHCs) with iminoboranes have been synthesized and isolated at low temperature (-45 °C). The adducts show short BN bonds and planarity at boron, mimicking the structures of the isoelectronic imine functionality. When di-tert-butyliminoborane was reacted with 1,3-bis(isopropyl)imidazol-2-ylidene (IPr), the initially formed Lewis acid-base adduct quickly rearranged to form a new carbene substituted with an aminoborane at the 4-position. Warming the iminoborane-CAAC adduct to room temperature resulted in an intramolecular cyclization to give a bicyclic 1,2-azaborilidine compound.
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg (Germany) http://www-anorganik.chemie.uni-wuerzburg.de/Braunschweig/index.html. h.braunschweig@mail.uni-wuerzburg.de.
authors.forename: Holger
authors.initials: H
authors.lastname: Braunschweig
authors.forename: William C
authors.initials: WC
authors.lastname: Ewing
authors.forename: K
authors.initials: K
authors.lastname: Geetharani
authors.forename: Marius
authors.initials: M
authors.lastname: Schäfer
keywords: boron; carbenes; iminoborane adducts; rearrangement