title: Quaternizing diboranes(4): highly divergent outcomes and an inorganic Wagner-Meerwein rearrangement.
abstract: Apart from a few compounds under heavy use in organic chemistry, diboranes are relatively exotic and poorly understood. Recently, interest in these molecules has intensified with the advent of so-called "sp(2)-sp(3)" diboranes which exhibit useful reactivity toward organic substrates. In our hands, addition of Lewis bases to dihalodiorganyl diboranes(4) has previously shown some very surprising reactivity, including a substituent exchange between the boron atoms, and diboranes in which halide atoms bridge the B-B bond. Herein we have expanded the range of diborane(4) and Lewis base reaction partners, in the process uncovering three new reactivity patterns as well as some cases where mixtures are obtained. Trends are established for the preferential formation of certain products which rationalize the results based on electronic and steric effects. The substituent exchange, clearly based on an inorganic version of the well-known Wagner-Meerwein rearrangement, was also found to be an equilibrium reaction with the halide-bridged Lewis adducts on the other side.
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany. h.braunschweig@uni-wuerzburg.de
authors.forename: Holger
authors.initials: H
authors.lastname: Braunschweig
authors.forename: Alexander
authors.initials: A
authors.lastname: Damme
authors.forename: Rian D
authors.initials: RD
authors.lastname: Dewhurst
authors.forename: Thomas
authors.initials: T
authors.lastname: Kramer
authors.forename: Thomas
authors.initials: T
authors.lastname: Kupfer
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Radacki
authors.forename: Eva
authors.initials: E
authors.lastname: Siedler
authors.forename: Alexandra
authors.initials: A
authors.lastname: Trumpp
authors.forename: Katharina
authors.initials: K
authors.lastname: Wagner
authors.forename: Christine
authors.initials: C
authors.lastname: Werner
mesh_terms: D001880:Boranes / Q000138:chemical synthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D015394:Molecular Structure; D011789:Quantum Theory
chemical_list: D001880:Boranes