title: Synthesis and structure of novel organocycloborates.
abstract: A series of alpha,omega-boryl(bromo)alkanes of the general formula R2B-(CH2)n-Br (n = 3, 4, 5, 6) was obtained in high yield following a standard hydroboration protocol. Upon treatment with Mg turnings and formation of the respective Grignard species, all alkanes with n = 4 to 6 underwent an unprecedented boron-centered cyclisation reaction with formation of boratacyclopentanes, -hexanes, and -heptanes, respectively. All new compounds were isolated in high yields as colourless, crystalline materials and characterised in solution by multinuclear NMR spectroscopy. Four representative examples were chosen for X-ray diffraction studies, thus providing the first structurally characterised ring systems of that size at a tetraalkyl borate centre.
authors.affiliation: Institut für Anorganische Chemie, Bayerische Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany. h.braunschweig@mail.uni-wuerzburg.de
authors.forename: Holger
authors.initials: H
authors.lastname: Braunschweig
authors.forename: Giovanni
authors.initials: G
authors.lastname: D'Andola
authors.forename: Tom
authors.initials: T
authors.lastname: Welton
authors.forename: Andrew J P
authors.initials: AJ
authors.lastname: White