title: Adduct Formation, B-H Activation and Ring Expansion at Room Temperature from Reactions of HBcat with NHCs.
abstract: We report the reactions of catecholborane (HBcat; 1) with unsaturated and saturated NHCs as well as CAAC(Me) . Mono-NHC adducts of the type HBcat⋅NHC (NHC=nPr2 Im, iPr2 Im, iPr2 Im(Me) , and Dipp2 Im) were obtained by stoichiometric reactions of HBcat with the unsaturated NHCs. The reaction of CAAC(Me) with HBcat yielded the B-H activated product CAAC(Me) (H)Bcat via insertion of the carbine-carbon atom into the B-H bond. The saturated NHC Dipp2 SIm reacted in a 2:2 ratio yielding an NHC ring-expanded product at room temperature forming a six-membered -B-C=N-C=C-N- ring via C-N bond cleavage and further migration of the hydrides from two HBcat molecules to the former carbene-carbon atom.
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Würtemberger-Pietsch
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Heidi
authors.initials: H
authors.lastname: Schneider
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany. todd.marder@uni-wuerzburg.de.
authors.forename: Todd B
authors.identifier: http://orcid.org/0000-0002-9990-0169
authors.initials: TB
authors.lastname: Marder
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany. u.radius@uni-wuerzburg.de.
authors.forename: Udo
authors.initials: U
authors.lastname: Radius
keywords: B-H bond activation; C-N bond cleavage; N-heterocyclic carbene; catecholborane; ring expansion reaction