Synthesis of Boriranes by Double Hydroboration Reactions of N-Heterocyclic Carbene Boranes and Dimethyl Acetylenedicarboxylate.
Timothy R McFadden, Cheng Fang, Steven J Geib, Everett Merling, Peng Liu, Dennis P Curran
Author Information
Timothy R McFadden: Department of Chemistry and ‡Computational Modeling & Simulation Program, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States.
Cheng Fang: Department of Chemistry and ‡Computational Modeling & Simulation Program, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States.
Steven J Geib: Department of Chemistry and ‡Computational Modeling & Simulation Program, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States.
Everett Merling: Department of Chemistry and ‡Computational Modeling & Simulation Program, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States.
Peng Liu: Department of Chemistry and ‡Computational Modeling & Simulation Program, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States. ORCID
Dennis P Curran: Department of Chemistry and ‡Computational Modeling & Simulation Program, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States.
Reaction of bis-(2,6-diisopropylphenyl)-imidazol-2-ylidene borane with dimethyl acetylenedicarboxylate gives 80% yield of a stable borirane (boracyclopropane) formed by formal double hydroboration along with 5% of the (E)-alkenylborane. DFT calculations suggest a mechanism where divergence to the two products occurs after a common initial stage of hydride transfer from the NHC-borane to the acetylenedicarboxylate.
