Phase-Transfer Catalyzed Asymmetric [4 + 1] Annulations for the Synthesis of Chiral 2,2-Disubstituted Tetrahydrothiophenes
作者:Qi Yin、Xiaolu Wen、Yiwei Chen、Xiangnan Gong、Lin Hu
DOI:10.1021/acs.orglett.1c02744
日期:2021.10.1
An efficient catalyticasymmetric [4 + 1] reaction, which features the use of simple β-keto esters as one-carbon nucleophiles and 5-succinimidothio-pent-2-enoates as four-atom bielectrophiles, has been developed in the presence of a bifunctional chiral phase-transfer catalyst. The new annulation provides a distinct protocol to access the functionalized 2-acyl-2-carboxyl tetrahydrothiophenes bearing
Regioselective Synthesis of Indolopyrazines through a Sequential Rhodium-Catalyzed Formal [3+3] Cycloaddition and Aromatization Reaction of Diazoindolinimines with Azirines
作者:Yonghyeon Baek、Chanyoung Maeng、Hyunseok Kim、Phil Ho Lee
DOI:10.1021/acs.joc.8b00115
日期:2018.2.16
A regioselective synthetic method for the preparation of indolopyrazines was demonstrated through a sequential Rh-catalyzed formal [3+3] cycloaddition and aromatization reaction of a wide range of diazoindolinimines with azirines. Because the previously reported synthetic methods afforded mixtures of indolopyrazines, the present method using unsymmetrical azirines has a strong advantage from a regioselectivity
Diastereoselective IBX Oxidative Dearomatization of Phenols by Remote Induction: Towards the Epicocconone Core Framework
作者:Agathe Boulangé、Philippe A. Peixoto、Xavier Franck
DOI:10.1002/chem.201101681
日期:2011.9.5
The IBX twist does it: Towards the synthesis of a recently isolated dihydropyranic azaphilone core framework, a 2‐iodoxybenzoic acid (IBX)‐mediatedoxidative dearomatization was performed on a bicyclic substrate with excellent diastereoselectivity. Trifluoroacetic acid (TFA) esters were obtained as single diastereomers and water was shown to increase both the speed and diastereoselectivity of the reaction
Highly enantioselective gem-chlorofluorination of active methylene compounds was carried out by using a copper(II) complex of a chiral spiro pyridyl monooxazoline ligand. This reaction yielded alpha-chloro-alpha-fluoro-beta-keto esters and alpha-chloro-alpha-fluoro-beta-keto phosphonates with up to 92% ee. The resulting dihalo beta-keto ester was converted into various alpha-fluoro-alpha-heteroatom-substituted carbonyl compounds via nucleophilic substitution without loss of optical purity. A fully protected beta-amino acid with a gem-chlorofluoromethylene function was also synthesized.