Abstract. We prove the existence of continuous boundary extensions (Cannon-Thurston maps) for the inclusion of a vertex space into a tree of (strongly) relatively hyperbolic spaces satisfying the qi-embedded condition. This implies the same result for inclusion of vertex (or edge) subgroups in finite graphs of (strongly) relatively hyperbolic groups. This generalizes a result of Bowditch for punctured surfaces in 3 manifolds and a result of Mitra for trees of hyperbolic metric spaces.
The
coupling of thioamides and donor/acceptor-substituted diazocarbonyl
compounds is reported for the first time. The present report provides
a mild, catalytic method that couples thioamides and donor/acceptor-substituted
diazocarbonyl compounds to form enamino esters and enaminones. Unlike
traditional methods for the synthesis of enamino esters and enaminones
from thioamides, both N-alkyl thioamides and thiocarbamates are suitable
substrates in this coupling reaction. Copper(I) bromide catalyzes
the reaction and provides enamino esters and enaminones chemo- and
diastereoselectively in less time than Rh
2
(OAc)
4
or Ru(PPh
3
)
3
Cl
2
catalysts.
Conjugation can lower
the energy barrier for unsaturated C–C
bond rotations, resulting in a mixture of equilibrating diastereomers
at room temperature. Therefore, methods claiming diastereoselective
synthesis of conjugated double bonds often require proof that the
observed diastereomeric ratio is not because of the diastereomeric
equilibration of the product. Variable-temperature (VT) NMR experiments
are commonly used to distinguish between the two possibilities. However,
the VT technique requires accessories for the NMR spectrometer and
more setup time. Here, we show that the rarely used application of
1-D and 2-D nuclear Overhauser effect spectroscopy experiments for
the detection of the equilibrating diastereomers is a convenient alternative
to the VT technique.
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