Just Published in Angewandte Chemie, International Edition

Authors: Dr. Merle Arrowsmith, Dominic Auerhammer, Dr. Rüdiger Bertermann, Prof. Dr. Holger Braunschweig, Prof. Dr. Gerhard Bringmann, Dr. Mehmet Ali Celik, Dr. Rian D. Dewhurst, Prof. Dr. Maik Finze, Dr. Matthias Grüne, Michael Hailmann, Thomas Hertle, Dr. Ivo Krummenacher

Abstract: Reduction of carbene-borane adduct [(cAAC)BBr2(CN)] (cAAC=1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) cleanly yielded the tetra(cyanoborylene) species [(cAAC)B(CN)]4 presenting a 12-membered (BCN)4 ring. The analysis of the Kohn–Sham molecular orbitals showed significant borylene character of the BI atoms. [(cAAC)B(CN)]4 was found to reduce two equivalents of AgCN per boron center to yield [(cAAC)B(CN)3] and fragmented into two-coordinate boron(I) units upon reaction with IMeMe (1,3,4,5-tetramethylimidazol-2-ylidene) to yield the corresponding tricoordinate mixed cAAC-NHC cyanoborylene. The analogous cAAC-phosphine cyanoborylene was obtained by reduction of [(cAAC)BBr2(CN)] in the presence of excess phosphine.

Link: http://onlinelibrary.wiley.com/doi/10.1002/anie.201608429/abstract