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An efficient approach to saccharin‐fused 1,4‐DHPs has been established by using a [3+3] annulation process. The chemical event was enabled by a Et3N‐catalyzed tandem Michael/aza‐Pinner reaction of alkyl cyclic N‐sulfonyl ketimines as nucleophiles with α,α‐dicyanoolefins. Under mild conditions, the desired products were readily prepared in good to excellent yields and with broad functional group tolerance (up to 95 % yield, 29 examples). Notably, this practical methodology features the synthesis of pentacyclic spirooxindoles bearing a quaternary spiro‐stereocenter. [ABSTRACT FROM AUTHOR]

An enantioselective Friedel–Crafts alkylation/cyclization tandem reaction of 3-aminophenols with α,α-dicyanoolefins has been performed successfully using a chiral dinuclear zinc catalyst, leading to a range of chiral 2-amino-4H-chromenes (up to 98% yield and >99% ee). To the best of our knowledge, this is the first asymmetric example of the dinuclear zinc-catalysed functionalization of aromatic C(sp2)–H bonds. [ABSTRACT FROM AUTHOR]

The oxirane and aziridine rings are valuable building blocks in modern synthetic chemistry and catalytic asymmetric ring opening reactions of these three membered ring systems have emerged as a powerful chemical tool for the synthesis of natural products and biologically active compounds. In this context, the regioselective ring‐opening of structurally or electronically unbiased epoxides and aziridines is challenging. Recently, metal‐catalyzed substrate directed strategies have successfully applied in the regio‐ and enantioselective ring opening of functionalized epoxy alcohols by the Yamamoto group. Subsequently, our group realized the ring opening reactions of functionalized 2,3‐aziridinyl alcohols with the dinuclear zinc complex. These enantioselective nucleophilic ring opening reactions of functionalized epoxy alcohols and aziridinyl alcohols allow for the facile synthesis of amino alcohol derivatives and the introduction of new concepts in catalysis. [ABSTRACT FROM AUTHOR]

Regio-reversed domino processes of triketone enones with azlactones have been established. Opposite to the previous β-addition-triggered domino processes, this protocol is initiated by a regio-reversed α-addition. Under catalyst-free conditions, the domino reaction readily occurred, leading to the formation of a variety of bicyclic furofurans bearing vicinal quaternary carbons in good to excellent yields. In addition, a catalytic asymmetric version was achieved using chiral phosphoric acid catalysis, in which H2O played a crucial role in enantio-control. Notably, all the prepared enantio-enriched products could be further recrystallized to ensure excellent enantioselectivity. [ABSTRACT FROM AUTHOR]

The first Zn-ProPhenol catalyzed asymmetric inverse-electron-demand Diels–Alder reaction has been accomplished. This protocol was carried out by a dual-activation mode under mild conditions, allowing the preparation of various biologically important dihydropyrans in good yields with excellent stereoselectivities. [ABSTRACT FROM AUTHOR]

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]

We report herein an enantioselective [3+3] annulation of indoline‐2‐thiones with yne–enones by chiral dinuclear zinc catalysts via a Brønsted base and Lewis acid cooperative activation model. This transformation proceeded through sequential conjugate addition, allenyl ketone formation and intramolecular sulfa‐Michael 6‐endo‐trig cyclization. A range of enantioenriched tetrahydrothiopyrano[2,3‐b]indole derivatives bearing an exocyclic double bond were obtained in moderate yields with excellent stereoselectivities (up to 20 : 1 dr, 20:1 Z/E ratio and 95% ee). Late‐stage functionalization, large‐scale experiment and further derivatizations were also explored. [ABSTRACT FROM AUTHOR]

The first regio‐, diastereo‐, and enantioselective direct Mannich reaction of β,γ,‐unsaturated ketones with benzoxazinone cyclic imines was enabled by Lewis acid/Brønsted base cooperative catalysis. The dinuclear zinc complex catalyzed the reaction of a broad range of β,γ‐unsaturated ketones to proceed at the α‐site exclusively, leading to corresponding adducts with two consecutive tertiary carbon stereocenters in diastereomeric ratios of up to >20:1 and enantioselectivities generally in the 90–99 % ee range. These products were used as general intermediates in the synthesis of multisubstituted cyclocanalines, tetrahydro pyridazinones, and 4H‐furo[2,3‐b][1,4]benzoxazine derivatives. [ABSTRACT FROM AUTHOR]

Herein, the first diversity‐oriented catalytic asymmetric dearomatization of indoles with o‐quinone diimides (o‐QDIs) is reported. The catalytic asymmetric dearomatization (CADA) of indoles is one of the research focuses in terms of the structural and biological importance of dearomatized indole derivatives. Although great achievements have been made in target‐oriented CADA reactions, diversity‐oriented CADA reactions are regarded as more challenging and remain elusive due to the lack of synthons featuring multiple reaction sites and the difficulty in precise control of chemo‐, regio‐, and enantio‐selectivity. In this work, o‐QDIs are employed as a versatile building block, enabling the chemo‐divergent dearomative arylation and [4 + 2] cycloaddition reactions of indoles. Under the catalysis of chiral phosphoric acid and mild conditions, various indolenines, furoindolines/pyrroloindolines, and six‐membered‐ring fused indolines are collectively prepared in good yields with excellent enantioselectivities. This diversity‐oriented synthesis protocol enriches the o‐quinone chemistry and offers new opportunities for CADA reactions. [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 success in the identification of the two enantioisomeric surfaces of electrophiles by dinuclear zinc catalysts is disclosed. This protocol realizes a dinuclear zinc‐cocatalyzed desymmetrization of cyclopentendiones using α‐hydroxy aryl ketones as nucleophiles through Michael addition reaction. Under mild conditions, a series of functional cyclopentanediones bearing multiple stereogenic centers including an all‐carbon quaternary stereocenter, were obtained in moderate to good yields with excellent stereoselectivities. [ABSTRACT FROM AUTHOR]

With a dinuclear zinc-ProPhenol complex as a catalyst, an efficient and novel [3 + 3] annulation of indoline-2-thiones and isatylidene malononitriles has been successfully developed via the Brønsted base and Lewis acid cooperative activation model. This practical methodology gives access to a broad range of chiral spiro[indoline-3,4′-thiopyrano[2,3-b]indole] derivatives in good yields with excellent levels of enantioselectivities (up to 88% yield and 99% ee). [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]

A simple base-mediated dearomatization [2 + 3] annulation of 2-nitrobenzofurans with 4-hydroxycoumarins has been reported. A series of polycyclic heterocycles bearing dihydrofurobenzofuran and coumarin blocks were synthesized via Michael/nucleophilic substitution cascade reaction in moderate to excellent yields. 2-Nitrobenzothiophene and 4-hydroxyquinolin-2-one are also tolerated in this protocol. The reaction can be carried out on a gram scale. The configuration of product is confirmed by X-ray single crystal structure analysis. [Display omitted] [ABSTRACT FROM AUTHOR]