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.
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