Journal of the American Chemical Society
COMMUNICATION
subsequent polymerization/oligomerization reactions of the
aminoborane MeNHdBH2, which appears to be present as a
metal-bound species. Thermal treatment leads to similar reac-
tions in the absence of the Ir catalyst, but the aminoborane is
“free” in solution and can be trapped with cyclohexene. The
observation of other side products led to the interesting dis-
covery that the model aminoborane iPr2NdBH2 can be hydro-
genated in reactions with diborazanes and amine-boranes in the
absence of a metal catalyst. The facile, room temperature
hydrogenation of the BdN bond in aminoboranes is of funda-
mental significance16 and also has other potential implications,
such as in the regeneration of amine-borane hydrogen storage
materials and the use of BꢀN compounds in metal-free catalysis.
These results are also important with respect to the mechanistic
considerations associated with metal-catalyzed group 13ꢀ15
dehydrocoupling reactions, as to date the focus has been almost
entirely on the role of the metal. Further studies in this intriguing
area are in progress in our group.
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’ ASSOCIATED CONTENT
S
Supporting Information. Experimental data and rele-
b
vant spectra. This material is available free of charge via the
’ AUTHOR INFORMATION
Corresponding Author
of MeNH2 BH3 and 0.3 mol % IrH2POCOP in the presence of
3
cyclohexene, indicating that any MeNHdBH2 formed remains bound
to the Ir center as previously proposed (ref 3b). (b) Percentages refer to
the proportion of soluble boron content, as calculated via integration of
the 11B NMR spectra. See the Supporting Information for further details.
(12) Pasumansky, L.; Haddenham, D.; Clary, J. W.; Fisher, G. B.;
Goralski, C. T.; Singaram, B. J. Org. Chem. 2008, 73, 1898.
(13) Heating a THF solution of iPr2NdBH2 and cyclohexene at
70 °C in THF over 20 h produced no reaction, with only unreacted
starting material apparent upon analysis by 11B NMR spectroscopy.
’ ACKNOWLEDGMENT
A.P.M.R., E.M.L., and I.M. acknowledge the EPSRC for
funding. We thank Dr. George R. Whittell for useful discussions.
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