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The Sc(III)-catalyzed [2,3]-sigmatropic rearrangement of sulfonium ylides derived from azoalkenes has been established. Owing to the absence of a carbenoid intermediate, this protocol represents the first non-carbenoid variant of the Doyle–Kirmse reaction. Under mild conditions, a variety of tertiary thioethers have been readily prepared in good to excellent yields. [ABSTRACT FROM AUTHOR]

This report has realized the catalytic asymmetric [3+2] annulation of benzylideneindolinones with CF3‐containing isatin‐derived azomethine ylides for the first time, in which the organocatalysis has failed. In the presence of dinuclear zinc catalysts, a series of functionalized 2,3‐pyrrolidinyl dispirooxindoles have been synthesized in good yields with excellent stereoselectivity under mild reaction conditions. This protocol can be run on a gram scale and a possible catalytic mechanism is proposed. [ABSTRACT FROM AUTHOR]

The application of dinuclear zinc catalysts in a dearomatization reaction has been developed. Catalytic asymmetric dearomatization [3+2] annulations of 2‐nitrobenzofurans or 2‐nitrobenzothiophenes with CF3‐containing N‐unprotected isatin‐derived azomethine ylides catalyzed by dinuclear zinc catalysts are realized with excellent diastereomer ratios (dr) of >20 : 1 and enantiomeric excess (ee) of up to 99 %. This protocol provides a practical, straightforward access to structurally diverse pyrrolidinyl spirooxindoles containing a 2,3‐fused‐dihydrobenzofuran (or dihydrobenzothiphene) moiety, and four contiguous stereocenters. Reactions can be performed on a gram scale. The absolute configuration of products is confirmed by X‐ray single crystal structure analysis, and a possible mechanism is proposed. [ABSTRACT FROM AUTHOR]