The reaction of a copper complex bearing iminosemiquinone ligands with a CF sub(3) super(+) source provides an unprecedented Cu super(II)-CF sub(3) complex through ligand-based oxidation. Reactivity ...of this complex leads to nucleophilic trifluoromethylation of the ligand, suggesting an electronic interplay that results in a formal umpolungof the initial CF sub(3) super(+).
Pyrane to oxepane in one step: Highly regio- and stereoselective homologations dependent on the nature of carbonyl function and catalysts have been observed during the formation of enoxysilanes. ...Trimethylsilyl trifluoromethanesulfonate (TMSOTf) and AlCl3 were identified as suitable catalysts to promote the homologation and ring-enlargement.
The reaction of a copper complex bearing iminosemiquinone ligands with a CF 3 + source provides an unprecedented Cu II –CF 3 complex through ligand-based oxidation. Reactivity of this complex leads ...to nucleophilic trifluoromethylation of the ligand, suggesting an electronic interplay that results in a formal umpolung of the initial CF 3 + .
2-Morpholin-4-yl-4-oxo-4H-chromen-8-yl 2,2,2-trifluoromethanesulfonate is a key intermediate for the synthesis of the DNA-dependent protein kinase (DNA-PK) inhibitor ...8-dibenzothiophen-4-yl-2-morpholin-4-yl-chromen-4-one (NU7441). Two improved methods for the synthesis of this triflate have been developed: (A) in 35% overall yield, through modification of the published route, and (B) in 15% overall yield, by a new route employing a Baker−Venkataraman rearrangement to enable generation of the chromenone scaffold. Both syntheses depend on the judicious use of allyl protecting groups.
The microscopic protonation mechanism, at an inframolecular level, of norbadione A, a pigment extracted from mushrooms and known to complex cesium cations, was determined by using 1H NMR titrations ...and the cluster expansion method. This study revealed a pH dependent Z to E isomer switch that occurs in both pulvinic moieties. As a consequence, norbadione A can exist in solution in four stereomeric forms (E−E, E−Z, Z−E, and Z−Z), which can be of interest in the development of molecular-level devices. In the presence of 0.15 M NaCl, the calculated microconstants showed an unusual apparent cooperativity between the enol groups, which results from the release of the sodium cations upon protonation of norbadione A.
Das permethylierte Analogon 1 des Pilzinhaltsstoffs Norbadion A wurde durch zweifache Suzuki‐Miyaura‐Kupplung des Naphthalindiboronsäureesters 2 mit dem Triflat 3 erhalten. ESI‐MS‐Untersuchungen ...zufolge sind die Komplexe des Dikaliumsalzes von Norbadion A und von 1 mit Caesium ähnlich stabil, d. h., die Caesium‐Komplexierung erfolgt sehr wahrscheinlich über die Pulvinsäure‐Einheiten beider Verbindungen.
