title: Generation of an N→B Ladder-type Structure by Regioselective Hydroboration of an Alkenyl-Functionalized Quaterpyridine.
abstract: An unusual reactivity of 2-(1-alkenyl)-pyridines towards hydroboration with 9H-borabicyclo[3.3.1]nonane (9H-BBN) has been employed to selectively introduce two borane groups into a conjugated quaterpyridine. Quantitative conversion of the substrate was observed with exclusive regioselectivity. A molecular structure that allows intramolecular N→B coordination was generated. The effect of the ladder formation on the molecular structure and the electronic properties of the conjugated system have been investigated. The synthetic strategy demonstrated herein offers a facile access to N→B ladder-type structures from readily available substrates, and allows to simultaneously introduce several boron centers under mild conditions.
authors.affiliation: Institute of Organic Chemistry II and Advanced Materials, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Grandl
authors.affiliation: Fachbereich Chemie, Technische Universität Kaiserslautern, Erwin-Schrödinger-Strasse 54, 67663, Kaiserslautern, Germany.
authors.forename: Yu
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Institute of Organic Chemistry II and Advanced Materials, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany. frank.pammer@uni-ulm.de.
authors.forename: Frank
authors.initials: F
authors.lastname: Pammer
keywords: aromatic compounds; electronic structure; heterocyclic compounds; hydroboration; regioselectivity