@unpublished{StennettMattockVollertetal.2018,
  author    = {Stennett, Tom and Mattock, James and Vollert, Ivonne and Vargas, Alfredo and Braunschweig, Holger},
  title     = {Unsymmetrical, Cyclic Diborenes and Thermal Rearrangement to a Borylborylene},
  series = {Angewandte Chemie, International Edition},
  volume    = {57},
  journal   = {Angewandte Chemie, International Edition},
  doi       = {10.1002/anie.201800671},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-160258},
  pages     = {4098-4102},
  year      = {2018},
  abstract  = {Cyclic diboranes(4) based on a chelating monoanionic, benzylphosphine linker were prepared by boron-silicon exchange between arylsilanes and B\(_2\)Br\(_4\). Coordination of Lewis bases to the remaining sp\(^2\) boron atom yielded unsymmetrical sp\(^3\)-sp\(^3\) diboranes, which were reduced with KC\(_8\) to their corresponding trans-diborenes. These compounds were studied by a combination of spectroscopic methods, X-ray diffraction and DFT calculations. PMe\(_3\)-stabilized diborene 6 was found to undergo thermal rearrangement to gem- diborene 8. DFT calculations on 8 reveal a polar boron-boron bond, and indicate that the compound is best described as a borylborylene.},
  language  = {en}
}
@unpublished{StennettMattockPentecostetal.2018,
  author    = {Stennett, Tom and Mattock, James and Pentecost, Leanne and Vargas, Alfredo and Braunschweig, Holger},
  title     = {Chelated Diborenes and their Inverse-Electron-Demand Diels- Alder Reactions with Dienes},
  series = {Angewandte Chemie, International Edition},
  journal   = {Angewandte Chemie, International Edition},
  doi       = {10.1002/anie.201809217},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178268},
  year      = {2018},
  abstract  = {A doubly base-stabilized diborane based on a benzylphosphine linker was prepared by a salt elimination reaction between 2-LiC\(_6\)H\(_4\)CH\(_2\)PCy\(_2\).Et\(_2\)O and B\(_2\)Br\(_4\). This compound was reduced with KC8 to its corresponding diborene, with the benzylphosphine forming a five-membered chelate. The diborene reacts with butadiene, 2-trimethylsiloxy-1,3-butadiene and isoprene to form 4,5-diboracyclohexenes, which interconvert between their 1,1- (geminal) and 1,2- (vicinal) chelated isomers. The 1,1-chelated diborene undergoes a halide-catalysed isomerisation into its thermodynamically favoured 1,2-isomer, which undergoes Diels-Alder reactions more slowly than the kinetic product.},
  language  = {en}
}