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.
<i>N</i>-Prolinylanthranilamide Pseudopeptides as Bifunctional Organocatalysts for Asymmetric Aldol Reactions
作者:Anthony J. Pearson、Santanu Panda
DOI:10.1021/ol202284n
日期:2011.10.21
Proline anthranilamide-based pseudopeptides were shown to be effective organocatalysts for enantioselective direct aldol reactions of a selection of aldehydes with various ketones with excellent yield, enantioselectivity up to 99% and anti to syn diastereoselectivity up to 25:1.
Enantioselective Synthesis of (<i>R</i>)-Convolutamydine A with New<i>N</i>-Heteroarylsulfonylprolinamides
N‐(2‐Thiophenesulfonyl)prolinamide could be easily introduced into Montmorillonite by a simple ion‐exchange reaction. The asymmetric aldolreactions between various isatins with acetone or acetaldehyde using a heterogeneous Montmorillonite‐entrapped organocatalyst afforded products with high enantioselectivity. The catalyst was readily reusable without significant loss of catalytic activity or enantioselectivity.