10.1002/chem.202004088
Chemistry - A European Journal
FULL PAPER
triazacyclohexane (TMTAC) to a solution of the fluorosilane 7 in
CDCl3 solution, a fine colourless solid precipitated. This solid
compound was insoluble in any common solvents and was
therefore not further investigated and characterised.
also attempted. However, none of those reactions led to identifi-
able or isolable products. In most cases no conversion was obser-
ved via 1H or 19F{1H} NMR spectroscopy. For those where a reac-
tion took place, the products decomposed over time or the substi-
tution of the acetylene bonds proceeded unsymmetrically or in-
completely.
Hydrometallation reactions
We attempted to use annulene derivatives 3 and 4 also in other
hydrometallation reactions, with hydrometallation reagents of the
elements of main group III (M = B, Al, Ga) and IV (M = Si, Sn). We
tried different methods and varied parameters like temperature,
reaction time or the solvent. In addition, some of the reactions
were conducted in the presence of a catalyst. The reagents and
parameters are shown in Table S1 in the Supporting Information.
Despite these many attempts and for none of these cases, we
were able to isolate the predicted products. In most of the
reactions we could not see a conversion, monitored by the
However, due to the high potential of the possibility to obtain
chalice-like compounds in a single step of synthesis we will test
parameters for other hydrometallation reagents in the future in
order to explore if the phenomenon of regio- and stereoselective
substitution can be extended to more examples than reported
herein.
Acknowledgements
1
corresponding resonances in H or 19F{1H} NMR spectroscopy.
We thank Klaus-Peter Mester and Marco Wißbrock for recording
NMR spectra and Barbara Teichner for elemental analyses. This
work was funded by Deutsche Forschungsgemeinschaft (DFG,
German Research Foundation, grant MI477/39-1, project number
424957011).
For such cases where a conversion could be observed, the gene-
rated products could not be identified or decomposed after a short
time. We suspected an incomplete and/or unsymmetrical sub-
stitution, because of the many different resonance patterns we
observed in the NMR spectra. The fact that only symmetrical
products were obtained for hydrosilylation with HSiCl3 and
HSiCl2Me is not fully understood. The analogous reaction with
HSiClMe2 under the same conditions did not lead to the predicted
products. On the one hand the acetylene bond might not be polar
enough for some of the reagents, on the other hand hydrometalla-
tion reagents, which are highly reactive, lead to unsymmetrical
products.
Keywords: annulenes • tridentate Lewis acids • chalice
structure • hydrosilylation • solid-state structures
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