Search

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]

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 catalytic asymmetric interrupted Attanasi reaction has been established. Under the catalysis of a bifunctional organocatalyst, the condensation of cyclic β-keto esters with azoalkenes readily occurred, delivering a variety of bicyclic fused 2,3-dihydropyrroles with vicinal quaternary stereogenic centers in good yields and with good to excellent enantioselectivities (27 examples, up to 96% yield and 95% ee). [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]

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]