Beilstein J. Org. Chem.2015,11, 2584–2590, doi:10.3762/bjoc.11.278
, for 2 and 3, respectively. The 1H NMR spectra of complexes 2 and 3 exhibited relatively broad signals, which may indicate a fluxionalbehavior. This may be likely caused by the combined rotation around the C–C sigma bonds of the tris-MIC ligand and the Ccarbene–M bond.
In order to widen the
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Graphical Abstract
Scheme 1:
Schematic representation of ligands A and B.
Beilstein J. Org. Chem.2013,9, 1419–1425, doi:10.3762/bjoc.9.159
Science Hall, Notre Dame, IN, 46556, USA 10.3762/bjoc.9.159 Abstract Dipolar addition of cyclic azomethine imines with cyclic vinyl sulfones gave rise to functionalized tricycles that exhibited fluxionalbehavior in solution at room temperature. The scope of the synthetic methodology was explored, and
the origin of the fluxionalbehavior was probed by NMR methods together with DFT calculations. This behavior was ultimately attributed to stereochemical inversion at one of two nitrogen centers embedded in the tricyclic framework. Two tetracycles were also synthesized, and the degree of signal
-broadening in the NMR spectra was found to depend on the presence of substitution next to the inverting nitrogen center.
Keywords: DFT calculations; dipolar addition; fluxionalbehavior; sulfones; VT NMR; Introduction
The 1,3-dipolar cycloaddition [1][2][3] represents a powerful methodology for the
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Graphical Abstract
Scheme 1:
Synthesis of a conformationally constrained bicyclic sulfone, and application as an inhibitor of an...