RESUMO
We present the PIFA-mediated intramolecular N-arylation of 2-aminoquinoxalines at room temperature for the first time. This method provides a wide range of indolo[2,3-b]quinoxalines in good to excellent yields within a short time. The C-H bond functionalization occurs without the need for an inert atmosphere or additives. Additionally, a double C-H bond functionalization was observed, where the first reaction forms a C-N bond (N-arylation) and the second forms a C-O bond, yielding an acetal-functionalized product. Mechanistic investigations suggest that the C-H bond functionalization proceeds through an ionic mechanism, whereas acetal functionalization follows a radical pathway. This method extends to the derivation of indoloquinoxalines, including the target compound BIQMCz.
RESUMO
The catalytic intermolecular arylation of disubstituted geminal dinitriles with in situ generated arylnickel complexes is disclosed. This method efficiently provides various all-carbon substituted α-cyanocarbonyl compounds without additives and an inert atmosphere. It also demonstrates the arylation of R-BINOL and S-BINOL derived geminal dinitriles, preserving optical purity. Mechanistic studies proved that the in situ generated organonickel complex is involved in arylation.
RESUMO
We disclose the first catalytic domino reaction of α-(2-formylaryloxy)acetonitriles with arylboronic acids, yielding a range of 2-aroylbenzo[b]furans with yields of up to 93%. Ni(acac)2 serves as an effective dual catalyst. The protocol is also applicable to α-(2-acetylphenoxy)acetonitrile, giving rise to 3-methyl-2-aroylbenzo[b]furans. This domino process is efficient, additive-free, and compatible with a variety of aryl boronic acids, including those with CF3, NO2, CN, and CO2Me groups. Mechanistic studies highlight the dual activation facilitated by the nickel catalyst.
