The diboranes(4) bis(catecholato)diborane (B₂Cat₂) and bis(pinacolato)diborane (B₂Pin₂) are important precursors for
organoboronic esters, which are versatile reagents for the formation of C–C bonds.

Holger Braunschweig and Frank Guethlein, Julius-Maximilians-Universität Würzburg, Germany, report a new one-step procedure for the synthesis of B₂Cat₂ and B₂Pin₂, by metal-mediated, catalytic dehydrocoupling of the commercially available boranes HBCat and HBPin.

Although the homocoupling of both boranes using both homogeneous and heterogeneous catalysts was successful, the practice of continuous removal of B₂Cat₂ and B₂Pin₂ provided a marked increase in efficiency. This effect was particularly salient in the synthesis of B₂Cat₂ with platinum on alumina, which proceeded with turnover numbers of up to 11 600. Further studies, including the use of different catalysts and boranes, are ongoing.

• Transition-Metal-Catalyzed Synthesis of Diboranes(4),
  Holger Braunschweig, Frank Guethlein,
  Angew. Chem. Int. Ed. 2011.
  DOI: 10.1002/anie.201104854