Asymmetric cross aldol addition of isatins with α,β-unsaturated ketones catalyzed by a bifunctional Brønsted acid–Brønsted base organocatalyst
作者:Guo-Gui Liu、Hua Zhao、Yu-Bao Lan、Bin Wu、Xiao-Fei Huang、Jian Chen、Jing-Chao Tao、Xing-Wang Wang
DOI:10.1016/j.tet.2012.03.042
日期:2012.5
The asymmetric cross-aldol reaction of isatins with α,β-unsaturated ketones has been developed under catalysis by a Cinchona alkaloid-derivated bifunctional Brønsted acid–Brønsted base catalyst, affording the aldol adducts in moderate to good yields (18–98%) with moderate to good enantioselectivities (30–97%). The noncovalent organo-catalyzed asymmetric cross-aldol reaction displays a broad substrate
Quinidine Thiourea-Catalyzed Aldol Reaction of Unactivated Ketones: Highly Enantioselective Synthesis of 3-Alkyl-3-hydroxyindolin-2-ones
作者:Qunsheng Guo、Mayur Bhanushali、Cong-Gui Zhao
DOI:10.1002/anie.201004161
日期:2010.12.3
New catalysis mechanism! The asymmetricaldolreaction of unactivated ketones and activated carbonyl compounds is realized with a quinidine‐derived thiourea catalyst (see scheme), and involves an enolate mechanism instead of the widely used enamine mechanism. With isatins as the substrate, the reaction can be applied to the enantioselective synthesis of biologically active 3‐hydroxyindolin‐2‐ones.