Enantioselective Synthesis of Multifunctionalized 4<i>H</i>-Pyrans via Formal [4 + 2] Annulation Process by Bifunctional Phosphonium Salt Catalysis
作者:Jia-Hong Wu、Jianke Pan、Juan Du、Xiaoxia Wang、Xuemei Wang、Chunhui Jiang、Tianli Wang
DOI:10.1021/acs.orglett.9b04079
日期:2020.1.17
highly enantioselective formal [4 + 2] annulation involving electron-deficient allenes as C2-synthons has been developed under bifunctional phosphonium salt catalysis. With this catalytic protocol, a wide range of synthetically interesting and highly functionalized chiral 4H-pyran derivatives were readily prepared in good yields (up to 99%) with outstanding diastereo- and enantioselectivities (up to
3-Chlorooxindoles: Versatile Starting Materials for Asymmetric Organocatalytic Synthesis of Spirooxindoles
作者:Artur Noole、Maksim Ošeka、Tõnis Pehk、Mario Öeren、Ivar Järving、Mark R. J. Elsegood、Andrei V. Malkov、Margus Lopp、Tõnis Kanger
DOI:10.1002/adsc.201300019
日期:2013.3.25
3‐Chlorooxoindoles have emerged as versatile precursors in the synthesis of spirocyclopropyl oxindoles. High enantio‐ and diastereoselectivity was attained under conditions of both iminium/enamine and H‐bonding catalysis.
Enantioselective Construction of 3-Hydroxy Oxindoles via Decarboxylative Addition of β-Ketoacids to Isatins
作者:Fangrui Zhong、Weijun Yao、Xiaowei Dou、Yixin Lu
DOI:10.1021/ol301855w
日期:2012.8.3
The first highlyenantioselectivedecarboxylativeaddition of β-ketoacids to isatins mediated by a bifunctional tertiary amine–thiourea catalyst has been developed, allowing facile synthesis of biologically important 3-hydroxyoxindoles in good yields and excellent enantioselectivities. The method reported represents a valuable approach of utilizing β-ketoacids as synthetic equivalents of aryl/alkyl
Asymmetric Organocatalytic Synthesis of Spiro-cyclopropaneoxindoles
作者:Tõnis Kanger、Artur Noole、Andrei Malkov
DOI:10.1055/s-0033-1338505
日期:——
Straightforward cascade reactions for the synthesis of spiro-cyclopropaneoxindoles are described. The target compounds are obtained in high yields and in good enantio- and diastereoselectivities via hydrogen bonding or iminium catalysis.