Organocatalytic Asymmetric Michael/Cyclization Cascade Reaction of 3-Isothiocyanato Oxindoles with Maleimides for the Efficient Construction of Pyrrolidonyl Spirooxindoles: Organocatalytic Asymmetric Michael/Cyclization Cascade Reaction of 3-Isothiocyanato Oxindoles with Maleimides for the Efficient Construction of Pyrrol

Synthesis of functionalized 3,2′-pyrrolidinyl spirooxindoles via domino 1,6-addition/annulation reactions of para-quinone methides and 3-chlorooxindoles

A highly efficient diastereoselective [4 + 1] cycloaddition of ortho-tosylaminophenyl-substituted p-QMs with 3-chlorooxindoles has been developed to afford 3,2′-pyrrolidinyl spirooxindoles.

Advances of α-activated cyclic isothiocyanate for the enantioselective construction of spirocycles

The efficient and enantioselective synthesis of pharmaceutically important spirocycles has attracted the focus of organic and medicinal chemists. In this context, with the excellent reactivity of α-activated isothiocyanate as formal 1,3-dipoles in the (3 + 2) cyclization process, the cyclic isothiocyanates featuring important pharmacophores, such as oxindole, pyrazolone, and indanone moieties, have emerged as powerful precursors to access a variety of spirocycles with highly structural diversities. In addition, the facile transformations of these spirocycles have shown potential applications in drug design. This review will cover the recent advances of α-activated cyclic isothiocyanates in the enantioselective construction of spirocycles since 2015, and the applications of corresponding products in organic and medicinal chemistry.

Stereoselective synthesis of trifluoroethyl 3,2'-spirooxindole γ-lactam through the organocatalytic cascade reaction of 3-((2,2,2-trifluoroethyl)amino)indolin-2-one

Newly designed 3-((2,2,2-trifluoroethyl)amino)indolin-2-ones were used for the facile synthesis of chiral fluoroalkyl-containing 3,2'-spirooxindole γ-lactam products. The secondary amine-catalysed Michael/hemiaminalization cascade reaction of 3-((2,2,2-trifluoroethyl)amino)indolin-2-one with α,β-unsaturated aldehydes followed by oxidation can easily produce the desired products in high yields (up to 86%) with excellent enantioselectivities (up to 99% ee) and diastereoselectivities (up to >95 : 5 dr).

Stereoselective synthesis and applications of spirocyclic oxindoles

This review summaries recent synthetic developments towards spirocyclic oxindoles and applications as valuable medicinal and synthetic targets.

Double Spirocyclization of Arylidene-Δ2-Pyrrolin-4-Ones with 3-Isothiocyanato Oxindoles

Arylidene-Δ2-pyrrolin-4-ones undergo organocatalyzed double spirocyclization with 3-isothiocianato oxindoles in a domino 1,4/1,2-addition sequence. The products contain three contiguous stereocenters (ee up to 98%, dr up to 99:1, 12 examples). The absolute configuration of the major diastereomer was determined by single crystal X-ray analysis. Along with heterocyclic Michael acceptors based on oxazolone, isoxazolone, thiazolidinone, pyrazolone, and pyrimidinedione, the reported results display the applicability of unsaturated Δ2-pyrrolin-4-ones (pyrrolones) for the organocatalyzed construction of 3D-rich pyrrolone-containing heterocycles.

New development in the enantioselective synthesis of spiro compounds

In this review we summarize the latest developments in the enantioselective synthesis of spirocompounds. The most important organometallic and organocatalytic methodologies are highlighted.

Organocatalytic Michael/cyclization cascade reactions of 3-isothiocyanato oxindoles with 3-trifluoroethylidene oxindoles: an approach for the synthesis of 3′-trifluoromethyl substituted 3,2′-pyrrolidinyl-bispirooxindoles

A series of 3′-trifluoromethyl substituted 3,2′-pyrrolidinyl-bispirooxindoles were constructed via an asymmetric Michael/cyclization cascade reaction.

Catalytic asymmetric synthesis of spirooxindoles: recent developments

The past four years have witnessed significant developments in the field of the catalytic asymmetric synthesis of spirooxindoles, and this feature article outlines the recent progress in this area, including the contributions of our group. This article is divided into sections according to the size and type of the generated spiro-ring fused at the C3-position of the oxindole core.

Non-Covalent Organocatalyzed Domino Reactions Involving Oxindoles: Recent Advances

The ubiquitous presence of spirooxindole architectures with several functionalities and stereogenic centers in bioactive molecules has been appealing for the development of novel methodologies seeking their preparation in high yields and selectivities. Expansion and refinement in the field of asymmetric organocatalysis have made possible the development of straightforward strategies that address these two requisites. In this review, we illustrate the current state-of-the-art in the field of spirooxindole synthesis through the use of non-covalent organocatalysis. We aim to provide a concise overview of very recent methods that allow to the isolation of unique, densely and diversified spirocyclic oxindole derivatives with high structural diversity via the use of cascade, tandem and domino processes.

Organocatalytic asymmetric domino Michael/O-alkylation reaction for the construction of succinimide substituted 3(2H)-furanones catalyzed by quinine

Asymmetric domino reaction of maleimides with γ-halogenated-β-ketoesters catalyzed by quinine is developed to give succinimide substituted 3(2H)-furanones in good enantioselectivities.

Direct N–H/α,α,β,β-C(sp3)–H functionalization of piperidine via an azomethine ylide route: synthesis of spirooxindoles bearing 3-substituted oxindoles

A protocol for the direct functionalization of N–H/α,α,β,β-C(sp³)–H of piperidine without any metal or external oxidants is reported.

Squaramide-catalyzed asymmetric Michael/cyclization cascade reaction of 3-isothiocyanato oxindoles with chalcones for synthesis of pyrrolidinyl spirooxindoles

An efficient method for the construction of pyrrolidinyl spirooxindoles with 3-isothiocyanato oxindoles and chalcones via a Michael/cyclization cascade reaction has been developed using squaramide. The products were obtained in high yields with excellent stereo selectivities.

Catalytic enantioselective cascade Michael/cyclization reaction of 3-isothiocyanato oxindoles with exocyclic α,β-unsaturated ketones en route to 3,2′-pyrrolidinyl bispirooxindoles

Cascade Michael/cyclization reactions between 3-isothiocyanato oxindoles and exocyclic α,β-unsaturated ketones are shown to proceed in the presence of a tertiary amino-squaramide catalyst and furnish 3,2′-pyrrolidinyl bispirooxindoles with excellent enantioselectivities (up to 99 : 1 er).

Organocatalyzed enantioselective Michael addition/cyclization cascade reaction of 3-isothiocyanato oxindoles with arylidene malonates

Both enantiomers of functionalized 3,2′-pyrrolidinyl spirooxindoles were obtainedviaa Michael-cyclization cascade reaction using pseudoenantiomeric cinchona alkaloid derived thiourea based bifunctional catalysts.