Enantioselective construction of multifunctionalized spirocyclohexaneoxindoles through organocatalytic Michael–Aldol cyclization of isatin derived alkenes with linear dialdehydes
Phosphine- and Nitrogen-Containing Lewis Base Catalyzed Highly Regioselective and Geometric Selective Cyclization of Isatin Derived Electron-Deficient Alkenes with Ethyl 2,3-Butadienoate
摘要:
An interesting phosphine-containing Lewis base catalyzed highly regioselective [3 + 2] cycloaddition and a novel nitrogen-containing Lewis base catalyzed highly geometric selective [4 + 2] cycloaddition of isatin derived alpha,beta-unsaturated diesters with alpha-allenic ester have been disclosed to give the corresponding cyclic products in good to excellent yields under mild conditions. A plausible reaction mechanism has also been proposed on the basis of previous literature and our own investigation.
Facile Synthesis of Spirooxindole-Cyclohexenes via Phosphine-Catalyzed [4 + 2] Annulation of <i>α</i>
-Substituted Allenoates
作者:Rongshun Chen、Xia Fan、Zhaozhong Xu、Zhengjie He
DOI:10.1002/cjoc.201700112
日期:2017.9
phosphine‐catalyzed [4 + 2] annulation of α‐substituted allenoate with exocyclic alkene moiety of oxindoles or indan‐1,3‐diones has been developed. Thus, under the catalysis of PPh3 (20 mol%), a series of spirooxindole‐ or spiroindan‐1,3‐dione‐cyclohexenes have been obtained in moderate to excellent yields and regioselectivity from the annulations of α‐methyl allenoates with 3‐methyleneoxindoles or 2‐methyleneindan‐1
Asymmetric Synthesis of Spiro-3,3′-cyclopropyl Oxindoles via Vinylogous Michael Initiated Ring Closure Reaction
作者:Abhijit Manna、Harshit Joshi、Vinod K. Singh
DOI:10.1021/acs.joc.2c02402
日期:2022.12.16
A novel organocatalytic cascade approach for the synthesis of spiro-cyclopropyl oxindole derivatives has been developed. The methodology is based on asymmetric vinylogous Michael addition of 4-nitroisoxazole derivatives to N-Boc isatylidene malonates followed by intramolecularalkylation. Its remarkable stereocontrol, wide substrate scope, and scalability highlight this new developed strategy. Moreover
The present study reports an asymmetric organocascade reaction of oxindole-derived alkenes with 3-bromo-1-nitropropane efficiently catalyzed by the bifunctional catalyst. Spirooxindole-fused cyclopentanes were produced in moderate-to-good isolated yields (15–69%) with excellent stereochemical outcomes. The synthetic utility of the protocol was exemplified on a set of additional transformations of the