Enantioselective Construction of Spiro[2H-pyran-3,4′-indoline] by a Systematic Michael/Reduction/Cyclization Sequence Triggered by the Asymmetric Conjugate Addition of Ketones to Isatylidenemalononitriles

Organocatalysed one-pot three component synthesis of 3,3'-disubstituted oxindoles featuring an all-carbon quaternary center and spiro[2H-pyran-3,4'-indoline]

A simple and efficient methodology for the one-pot synthesis of 3,3'-disubstituted oxindoles featuring an all-carbon quaternary center has been demonstrated through l-proline catalysed three-component reaction based on sequential Knoevenagel condensation/Michael addition and also one-pot synthesis of spiro[2H-pyran-3,4'-indoline] through consecutive Knoevenagel condensation/Michael addition/reduction/cyclization reactions from readily available isatin derivatives, malononitrile, and ketones. The present methodology presents several advantages, including simple reaction set-up, short reaction times, and easy to work-up. Also, this strategy offers broad substrate scope with excellent yields and high atom economy, under mild reaction conditions.

Organocatalytic asymmetric spirocyclization reactions of cyclic 2,4-dienones with cyanoketones: synthesis of spiro-dihydropyrano cyclohexanones

The first organocatalytic asymmetric synthesis of spiro-dihydropyrano cyclohexanones has been developed via the cascade reaction between cyanoketones and cyclic 2,4-dienones. A cinchona alkaloid-derived bifunctional primary amine catalyst in combination with N-Boc-tleucine was found to be the most effective for this spirocyclization reaction and provided the desired products in moderate to good yields with high enantioselectivities.

Dinuclear zinc cooperative catalytic three-component reactions for highly enantioselective synthesis of 3,3′-dihydrofuran spirooxindoles

A new dinuclear zinc cooperative catalytic enantioselective three-component reaction via a domino Knoevenagel/Michael/cyclization sequence has been developed.

A dynamic kinetic asymmetric transfer hydrogenation–cyclization tandem reaction: an easy access to chiral 3,4-dihydro-2H-pyran-carbonitriles

A catalytic enantioselective dynamic kinetic asymmetric transfer hydrogenation–cyclization tandem reaction is developed for 1,3-difunctionalized racemic ketones.

Enantioselective synthesis of spiro[indoline-3,4′-pyrano[2,3-c]pyrazole] derivatives via an organocatalytic asymmetric Michael/cyclization cascade reaction

Pyrazolones have been firstly employed to react with isatylidene malononitriles, and chiral multicyclic spirooxindoles have been constructed with a low loading of commercially available catalysts.

Molecular sieve mediated sequential Knoevenagel condensation/decarboxylative Michael addition reaction: efficient and mild conditions for the synthesis of 3,3-disubstituted oxindoles with an all carbon quaternary center

A mild, catalyst-free and efficient molecular sieve mediated sequential Knoevenagel condensation/decarboxylative Michael additon reaction has been developed. A broad scope of 3,3-disubstituted oxindoles were synthesized in good to excellent yields.

A phosphotungstic acid-supported multifunctional organocatalyst containing 9-amino(9-deoxy)epi-cinchonidine and Brønsted acid and its application in asymmetric aldol reaction

Phosphotungstic acid-supported multifunctional 9-amino(9-deoxy)epi-cinchonidine containing Brønsted acid was developed through facile precipitation for the first time and afforded aldol adducts in excellent catalytic performance with good reusability.

Organocatalytic tandem enantioselective Michael-cyclization of isatin-derived β,γ-unsaturated α-ketoesters with 3-hydroxy-4H-chromen-4-one or 2-hydroxy-1,4-naphthoquinone derivatives

An efficient tandem Michael-cyclization has been reported to provide two types of enantio-enriched spiro-oxindole derivatives in high yields with excellent stereoselectivities.

Molecular diversity of spirooxindoles. Synthesis and biological activity

Spirooxindoles are important synthetic targets possessing extended biological activity and drug discovery applications. This review focuses on the various strategies for the enantioselective synthesis of spirocyclic oxindoles relying on reports over the past decade and from earlier work. The spirooxindoles in this review are separated into three structural classes, and then further categorized into the method type from which the spirocycle is generated.

Enantioselective assembly of functionalized carbocyclic spirooxindoles using anl-proline derived thiourea organocatalyst

Enantioselective sequential vinylogous Michael addition–cyclization reactions of vinyl malononitriles with isatylidene malononitrile were accomplished usingl-proline derived bifunctional thiourea.

Biocatalytic one-pot three-component synthesis of 3,3′-disubstituted oxindoles and spirooxindole pyrans using α-amylase from hog pancreas

α-Amylase from hog pancreas displayed catalytic promiscuity in three-component reaction for the synthesis of 3,3′-disubstituted oxindoles and spirooxindole pyrans.

Ordered short channel mesoporous silica modified with 1,3,5-triazine–piperazine as a versatile recyclable basic catalyst for cross-aldol, Knoevenagel and conjugate addition reactions with isatins

A recyclable triazine–piperazine immobilized silica supported material was explored as a heterogeneous catalyst for indole skeletal synthesized from isatins at RT.

Primary-tertiary diamine-catalyzed Michael addition of ketones to isatylidenemalononitrile derivatives

Simple primary-tertiary diamines easily derived from natural primary amino acids were used to catalyze the Michael addition of ketones with isatylidenemalononitrile derivatives. Diamine 1a in combination with D-CSA as an additive provided Michael adducts in high yield (up to 94%) and excellent enantioselectivity (up to 99%). The catalyst 1a was successfully used to catalyze the three-component version of the reaction by a domino Knoevenagel–Michael sequence. The Michael adduct 4a was transformed into spirooxindole 6 by a reduction with sodium borohydride in a highly enantioselective manner.