RESUMEN
CuH-catalyzed intramolecular cyclization and intermolecular allylation of benzimidazoles with allenes have been described. The reaction proceeded smoothly with the catalytic system of Cu(OAc)2/Xantphos and catalytic amount of (MeO)2MeSiH. This protocol features mild reaction conditions and a good tolerance of substrates bearing electron-withdrawing, electron-donating, or electron-neutral groups. A new catalytic mechanism was proposed for this copper hydride catalytic system.
RESUMEN
The development of universal catalyst systems that enable efficient, selective, and straightforward chemical transformations is of immense scientific importance. Here we develop a domino process comprising three consecutive reaction steps based on the strategy of supramolecular substrate recognition. This approach provides valuable ß-aryl aldehydes from readily accessible α-alkynoic acids and arenes under mild reaction conditions, employing a supramolecular Rh catalyst containing an acylguanidine-bearing phosphine ligand. Furthermore, the synthesis of a key intermediate of Avitriptan using this protocol is accomplished. The first step of the reaction sequence is proved to be the regioselective hydroformylation of α-alkynoic acids. Remarkably, molecular recognition of the ligand and the substrate via hydrogen bonding plays a key role in this step. Control experiments indicate that the reaction further proceeds via 1,4-addition of an arene nucleophile to the unsaturated aldehyde intermediate and subsequent decarboxylation.
RESUMEN
A Pd-catalyzed direct C-H trisallylation of azoles with alkyne has been described. A consecutive C(sp2)-H allylation/olefin isomerization/double C(sp3)-H allylation of azoles and alkyne via a palladium catalysis system proceeds efficiently to afford the corresponding C2-alkenylated azoles containing an all quaternary carbon center.
RESUMEN
A simple and mild protocol for copper(I)-mediated sulfonylation of 8-aminoquinoline amides with sulfonyl chlorides was developed, affording desired products in moderate to good yields. This reaction proceeds in air and features excellent substrate tolerance, especially for aliphatic sulfonyl chlorides.