RESUMEN
We report the catalytic generation of pyridyl radicals through photoexcitation of the electron donor-acceptor (EDA) complex, which enables the C2-selective heteroarylation of indole under ambient conditions. In this manifold, catalytic triarylamine and chloropyridine aggregate into an EDA complex in the presence of an inorganic base, making readily available chloropyridines good precursors for the generation of diverse pyridyl radicals. Given the broad reaction scope, this catalytic EDA complex protocol provides robust access to heterobiaryl scaffolds that are widely present in biologically important molecules.
RESUMEN
Starting from a hitherto unknown 2-aminotribenzotriquinacene, several 2-amino-3-X-substituted TBTQ derivatives, all bearing a single ortho-difunctionalized indane wing, were synthesized as rigid and chiral building blocks for the potential construction of complex supramolecular architectures. Efficient access to two pairs of enantiomeric TBTQ derivatives, namely, the peripheral ortho-nitroaniline (X = NO2) and the related anthranilic acid (X = CO2H), was developed using chiral auxiliaries as the resolving reagents. The structure of the intermediate diastereomers was confirmed by 1H and 13C NMR spectroscopy, high-resolution mass spectroscopy (HRMS), and polarimetry. The absolute configuration of the optically active derivatives was confirmed by quantum chemical time-dependent density functional theory (TD-DFT) calculations of the theoretical electronic circular dichroism (ECD) spectra and by single-crystal X-ray structure analysis of a synthesis intermediate.
RESUMEN
A copper(I)-catalyzed interrupted click reaction in the presence of trifluoroacetic anhydride has been developed, wherein an N-trifluoroacetyl group is used to accelerate the ring-opening of the putative 5-copper(I) triazolide intermediate. Under the optimized reaction conditions, a broad range of azides and alkynes were found to participate in this transformation, thus affording 3-trifluoromethyl-substituted 1,2,4-triazinones in moderate to excellent yields. The reaction has proven to be compatible with a variety of electron-withdrawing and electron-donating groups, halogens, and nitrogen- and sulfur-containing heterocycles, as well as pharmaceutically relevant molecules.