Crystal Structure of a Chiral Titanium Catalyst-Alkene Complex. The Intermediate in Catalytic Asymmetric Diels-Alder and 1,3-Dipolar Cycloaddition Reactions
Solvent-free asymmetric vinylogous aldol reaction of Chan's diene with aromatic aldehydes catalyzed by hydrogen bonding
摘要:
Chan's diene proved to react with aromatic aldehydes under organocatalytic conditions in presence of a chiral naphthyl-TADDOL derivative to give vinylogous aldols (up to 65% ee) with complete gamma-selectivity. A further process of hetero-Diels-Alder cycloaddition, leading to chiral pyran-4-one derivatives (up to 60% ee), was favoured by electron-withdrawing substituents on the aromatic ring. (C) 2009 Elsevier Ltd. All rights reserved.
Enantioselective Direct Synthesis of <i>syn</i>
- and <i>anti</i>
-α,β-Dihydroxy γ-Keto Esters Using a Dinuclear Zinc-AzePhenol Complex
作者:Zhao-Fei Zhang、Xiao-Chao Yang、Hui-Jie Lu、Min-Can Wang
DOI:10.1002/ejoc.201701695
日期:2018.2.14
A one‐step enantioselective directsynthesis of both syn‐ and anti‐α,β‐dihydroxy γ‐keto esters using a dinuclear zinc–AzePhenol complex is presented. This asymmetric α‐hydroxyacetate aldolreaction proceeds in moderate to good yield and with excellent enantioselectivity of up to 99 % ee. The desired products could be used as versatile intermediates for several transformations.
Crystal Structure of a Chiral Titanium Catalyst-Alkene Complex. The Intermediate in Catalytic Asymmetric Diels-Alder and 1,3-Dipolar Cycloaddition Reactions
作者:Kurt V. Gothelf、Rita G. Hazell、Karl Anker Jorgensen