Organocatalytic Asymmetric Michael Addition of Oxindoles to Nitroolefins for the Synthesis of 2,2-Disubstituted Oxindoles Bearing Adjacent Quaternary and Tertiary Stereocenters
A bifunctional thiourea-catalyzed Michael addition of activated indolin-3-ones to nitroolefins has been developed. The synthetically useful 2,2-disubstituted indolin-3-one derivatives with vicinal chiral quaternary–tertiary stereocenters were obtained in high yields with excellent stereoselectivities. The adduct can be readily transformed into a structurally interesting heterocyclic architecture by
Organocatalytic Enantioselective Michael Addition of 3-Indolinone-2-Carboxylates to Maleimides
作者:Suresh Yarlagadda、C. Ravikumar Reddy、Boora Ramesh、G. Ravi Kumar、B. Sridhar、B. V. Subba Reddy
DOI:10.1002/ejoc.201701670
日期:2018.3.22
The asymmetric conjugate addition of 2‐substituted 3‐indolinones to maleimides has been achieved by using a chiral bifunctional squaramide as an organocatalyst. This method provides easy access to 3‐indolinone‐2‐carboxylate‐succinimide adducts in high yields with exellent diastereo‐ and enantioselectivities.
Unexpected Insertion of Nitrogen into a C–C Bond: Access to 2,3-Disubstituted Quinazolinone Scaffolds
作者:Hui-Li Liu、Xiao-Tong Li、Heng-Zhi Tian、Xing-Wen Sun
DOI:10.1021/acs.orglett.1c01235
日期:2021.6.18
A novel, practical, highly efficient, and transition metal free nitrogeninsertion reaction for the synthesis of 2,3-disubstituted quinazolinone derivatives was developed. Diverse functionalized 3-indolinone-2-carboxylates and nitrosoarenes with a wide range of substituted nitrosobenzenes, nitrosopyridines, dibenzofuranyl, or dibenzothienyl nitroso compounds worked smoothly to give 2,3-disubstituted
Organocatalytic Enantioselective Amination of 2-Substituted Indolin-3-ones: A Strategy for the Synthesis of Chiral α-Hydrazino Esters
作者:Suresh Yarlagadda、B. Ramesh、C. Ravikumar Reddy、L. Srinivas、B. Sridhar、B. V. Subba Reddy
DOI:10.1021/acs.orglett.6b03473
日期:2017.1.6
An efficient enantioselective α-amination of 2-substituted 3-indolinones has been achieved for the first time using hydroquinidine as a chiral catalyst through an aza-Michael reaction. The desired α-hydrazino esters are obtained in excellent yields with high enantiomeric excess leading to a quaternary stereocenter with a broad substrate scope.
Asymmetric Robinson Annulation of 3-Indolinone-2-carboxylates with Cyclohexenone: Access to Chiral Bridged Tricyclic Hydrocarbazoles
作者:Suresh Yarlagadda、G. S. Sankaram、Sridhar Balasubramanian、B. Venkata Subba Reddy
DOI:10.1021/acs.orglett.8b01575
日期:2018.7.20
A chiral bifuntional thiourea catalyzed diastereo- and enantioselective Michael addition followed by an intramolecular Aldol reaction of 3-indolinone-2-carboxylates with cyclohexenone has been accomplished using a chiral thiourea catalyst. It is a novel strategy for the construction of chiral bridged tricyclic hydrocarbazole derivatives bearing four contiguous stereocenters with excellent diastereo-