Synthesis of dispiro[1-benzothiophene-2,3'-pyrrolidine-2',3”-indoline]-2”,3-diones in cycloaddition reaction

Copper-Catalyzed [4 + 1] Annulation of Enaminothiones with Indoline-Based Diazo Compounds

A concise synthetic route to spiroindoline-fused S-heterocycles was developed through copper-catalyzed [4 + 1] annulation using enaminothiones as donor-acceptor synthons. Both 3-diazoindolin-2-imines and 3-diazooxindoles were amenable to work as effective C1 building blocks. The reaction proceeds via a copper-catalyzed cascade process involving the in situ generation of copper(I) carbene and C-S/C-C bond formation. This synthetic protocol features the use of readily available substrates, diverse substituent tolerance, and good to excellent yields.

Catalytic asymmetric aromatizing inverse electron-demand [4+2] cycloaddition of 1-thioaurones and 1-azaaurones

Using 1-thioaurones and 1-azaaurones as electron-deficient oxa-dienes, an organocatalytic asymmetric aromatizing inverse electron-demand [4+2] cycloaddition with γ-deconjugated butenolides and azlactones was developed. A wide range of optically active benzothiophene-fused δ-lactones and indole-fused δ-lactones were obtained with desirable outcomes (up to 94% yield, >99 : 1 dr and 99% ee).