Highly Enantioselective Michael Addition of 2-Oxindole- 3-carboxylate Esters to Nitroolefins Promoted by Cinchona Alkaloid-Thiourea-Brønsted Acid Cocatalysts
作者:Xianjie Chen、Wei Zhu、Wangke Qian、Enguang Feng、Yu Zhou、Jinfang Wang、Hualiang Jiang、Zhu-Jun Yao、Hong Liu
DOI:10.1002/adsc.201200206
日期:2012.8.13
A highly efficient organocatalyzed Michael addition of 2-oxindole-3-carboxylate esters to nitroolefins using a Cinchona alkaloid-thiourea and an achiral Brønsted acid as cooperative organocatalysts is reproted that affords significantly improved enantioselectivity and diastereoselectivity. It also provides an efficient approach to the synthesis of spirooxindole derivatives with high enantioselectivity
Herein, a copper catalyzed asymmetric propargylation of 2-oxindole-3-carboxylate esters with terminal propargylic esters is described. This strategy successfully provides a direct approach to constructing a broad range of chiral C3-tetrasubstituted oxindoles with contiguous tertiary and quaternary carbon stereocenters in high yields and excellent enantioselectivities (16 examples, up to 99% yield and
Oxidative Dimerization of 2-Oxindoles Promoted by KO<sup><i>t</i></sup>Bu-I<sub>2</sub>: Total Synthesis of (±)-Folicanthine
作者:Santanu Ghosh、Saikat Chaudhuri、Alakesh Bisai
DOI:10.1021/acs.orglett.5b00032
日期:2015.3.20
A transition-metal-free oxidative coupling of 2-oxindoles has been demonstrated in the presence of 1.2 equiv each of potassium tert-butoxide and iodine. The method yields a diverse range of structurally different homo- and heterodimerized 2-oxindoles bearing vicinal all-carbon quaternary centers of great synthetic importance. A radical-driven pathway has been tentatively proposed.