cycloaddition of β-substituted ene- and thioenecarbamates as well as cyclic enamides with quinone diimides catalyzed by a BINOL- and SPINOL-derived phosphoric acid is reported. A wide variety of 2,3-disubstituted 2-aminoindolines, including polycyclic ones, were prepared in generally high yields (up to 98%) with moderate to complete diastereoselectivities and in most cases excellent enantioselectivities
A photoredox-catalzyed trifluoromethylation of enecarbamates process is reported. This pathway uses Togni's reagent as the CF3 source and follows a radical/cationic pathway. Under the optimized conditions using [Ru(bpy)(3)(PF6)(2)] as the photocatalyst, a wide range of substituted enecarbamates can readily be difunctionalized by means of various O, N, and C nudeophiles.
Ion-pairing catalysis in the enantioselective addition of hydrazones to <i>N</i>-acyldihydropyrrole derivatives
作者:Nagore Zabaleta、Uxue Uria、Efraim Reyes、Luisa Carrillo、Jose L. Vicario
DOI:10.1039/c8cc05311a
日期:——
demonstrated that dihydropyrrole-based enamide derivatives can act as efficient precursors of chiral quaternary N-acyliminium salts under Brønsted acid catalysis that undergo reactions with hydrazones, the latter participating as masked nucleophilic carbonyl group equivalents. The optimized methodology provides a variety of enantiopure α-substituted proline derivatives in excellent yields, being even compatible
become one: Phosphoric acid‐catalyzed enantioselective three‐component Povarovreactions of aldehydes, anilines, and endocyclic enethioureas have been developed (see scheme). This process afforded hexahydropyrroloquinolines in high yields with excellent diastereo‐ and enantioselectivities. The presence of the thiourea functionality is crucial for the enantioselectivity of the reaction.