Thiourea-catalyzed asymmetric domino Michael-cyclization reaction of 3-isothiocyanato oxindoles with beta,gamma-unsaturated alpha-keto esters for the synthesis of spirocyclic oxindoles

摘要

A reaction between 3-isothiocyanato oxindoles and beta,gamma-unsaturated alpha-keto esters catalyzed by a chiral thiourea organocatalyst via a domino Michael-cyclization process is described, which delivers a range of biologically important 2'-thioxospiro[indoline-3,4'-oxazolidin]-2-one compounds in high yields with good diastereo- and enantioselectivities (up to 99% yield, >99:1 dr, >99% ee). Moreover, two of 2'-thioxospiro[indoline-3,4'-oxazolidin]-2-one compounds were found to significantly behave in antiinflammatory activities in a preliminary biological evaluation. (C) 2019 Published by Elsevier Ltd.