A facile and selective route to remarkably inert monocyclic NHC-stabilized boriranes

Abstract

Herein we report a facile and selective synthetic route to monocyclic NHC-stabilized boriranes. We have succeeded in obtaining two highly stable new boriranes through salt elimination of NHC-stabilized dichloroboranes with the dianion of trans-stilbene, Na₂[C₁₄H₁₂]. One borirane was observed to undergo reaction with [Pt(PEt₃)₃], in which the Pt(0) center oxidatively adds a backbone C–H bond of the NHC, leading to the isolation of the Pt(II) complex trans-[(Et₃P)₂PtH{CCH(NMe)₂C·BPh(C₁₄H₁₂)}]. The remarkable inertness of the NHC-boriranes suggests a strong stabilising effect of quaternization of the boron atom.