An enantioselective alpha-amination of aryl oxindoles catalyzed by a dimeric quinidine has been developed. The reaction is general, broad in substrate scope, and affords the desired products in good yields with good to excellent enantioselectivities. This study provides the first examples of a general organocatalytic method for the creation of nitrogen-containing, tetrasubstituted chiral centers at C-3 of various aryl oxindoles. Furthermore, new catalysts and insights into structural elements of the catalysts that significantly influence enantioselectivities are disclosed.
An enantioselective alpha-amination of aryl oxindoles catalyzed by a dimeric quinidine has been developed. The reaction is general, broad in substrate scope, and affords the desired products in good yields with good to excellent enantioselectivities. This study provides the first examples of a general organocatalytic method for the creation of nitrogen-containing, tetrasubstituted chiral centers at C-3 of various aryl oxindoles. Furthermore, new catalysts and insights into structural elements of the catalysts that significantly influence enantioselectivities are disclosed.
An efficient, chiralbifunctional phase-transfer catalyst with an intramolecular amino functionality has been designed and successfully applied to highly enantioselective amination of 3-aryloxindoles and 3-arylbenzofuran-2(3H)-ones with bis(adamantyl) azodicarboxylate. Optically active amination products were generally obtained in high yield with high enantioselectivity. The origin of stereoselectivity
Bifunctional thiourea-modified polymers of intrinsic microporosity for enantioselective α-amination of 3-aryl-2-oxindoles in batch and flow conditions
作者:Laura Martín、Alicia Maestro、José M. Andrés、Rafael Pedrosa
DOI:10.1039/d0ob01373k
日期:——
Two novel polymers of intrinsic microporosity decorated with chiral thioureas have been used as recoverable organocatalysts in enantioselectiveα-amination of 3-aryl-substituted oxindoles, creating a quaternary stereocenter. Both catalysts were able to promote the reaction in excellent yields and good enantioselection. Catalyst II, with a pyridyl nucleus, was used in recycling experiments maintaining