Diastereo- and Enantioselective [3 + 2] Cycloaddition Reaction of Morita–Baylis–Hillman Carbonates of Isatins with N-Phenylmaleimide Catalyzed by Me-DuPhos

Phosphine-Catalyzed Stereospecific and Enantioselective Desymmetrizative [3+2] Cycloaddition of MBH Carbonates and N-(2-tert-Butylphenyl)maleimides

Herein, we report an l-valine-derived amide phosphine-catalyzed [3+2] cyclization of MBH carbonates and N-(2-tert-butylphenyl)maleimides via asymmetric desymmetrization. Bicyclic N-aryl succinimide derivatives bearing three continuous chiral centers with a remote C-N atropisomeric chirality were constructed stereospecifically and enantioselectively. A wide variety of MBH carbonates could be employed in this process to deliver highly optically pure succinimide derivatives in moderate to excellent yields.

Construction of diazepine-containing spiroindolines via annulation reaction of α-halogenated N-acylhydrazones and isatin-derived MBH carbonates

A straightforward synthetic protocol for the efficient construction of diazepine-containing spiroindolines has been developed and proceeds through a by base-promoted annulation reaction of α-halogenated N-acylhydrazones and isatin-derived MBH carbonates. The reaction mechanism of this formal [4 + 3] annulation includes the in situ generated allylic ylide, nucleophilic substitution, Michael additon, and elimination processes. Additionally, the similar reaction with α-halogenated N-tosylhydrazones also afforded N-tosyl-substituted spiro[indoline-3,5'-[1,2]diazepine] in satisfactory yields. This protocol provides a convenient approach for the assembly of diverse highly functionalized spiro[indoline-3,5'-[1,2]diazepines] and also features a broad substrate scope, simple reaction conditions, and high molecular convergence.

Phosphine-Catalyzed Atroposelective Formal [3 + 2] Cycloaddition Desymmetrization of N-Arylmaleimides

Herein, a new strategy for the enantioselective synthesis of axially chiral N-aryl succinimides was devised by [3 + 2] annulation of MBH carbonates and N-aryl maleimides under chiral phosphine. This desymmetrization process allows for quick construction of both two stereogenic carbon centers and a remote C_Ar-N atropisomeric chirality. A series of structurally diverse N-aryl succinimides were obtained with good to excellent yields, diastereoselectivities, and enantioselectivities. The process is mild, efficient, and scalable and features a broad substrate scope.

Tri(n-butyl)phosphine-promoted domino reaction for the efficient construction of spiro[cyclohexane-1,3'-indolines] and spiro[indoline-3,2'-furan-3',3''-indolines]

The tri(n-butyl)phosphine-catalyzed reaction of isatylidene malononitriles and bis-chalcones in chloroform at 65 °C afforded functionalized spiro[cyclohexane-1,3'-indolines] in good yields and with good diastereoselectivity. On the other hand, the tri(n-butyl)phosphine-catalyzed reaction of 3-(ethoxycarbonylmethylene)oxindoles and bis-chalcones gave functionalized spiro[cyclohexane-1,3'-indolines] with different regioselectivity. Additionally, the tri(n-butyl)phosphine-promoted domino annulation reaction of isatins and ethyl isatylidene cyanoacetates produced spiro[indoline-3,2'-furan-3',3''-indolines] in satisfactory yields.

Organocatalytic Regio- and Enantioselective [3 + 2]-Annulations of Ninhydrin-Derived Morita-Baylis-Hillman Carbonates with 3-Methyleneoxindoles

A type of Morita-Baylis-Hillman (MBH) carbonates has been developed from ninhydrin. These MBH carbonates have been successfully employed as 3C-synthons in the organocatalytic asymmetric [3 + 2]-annulations of the isatin-derived electron-deficient olefins, affording structurally diverse spirooxindoles in high yield with excellent stereoselectivity. In particular, the regioselectivity of MBH carbonates was controlled by the reaction partner, 3-methyleneoxindoles with carbonyl groups (R = ArCO), affording β-selective products and 3-methyleneoxindoles with ester groups (R = CO₂Me) furnishing γ-selective products. The representative scale-up reactions and transformation of product were examined. The reaction mechanism was expounded by control experiments.

Asymmetric hydrogenation of 1,4-diketones: facile synthesis of enantiopure 1,4-diarylbutane-1,4-diols

Owing to the biological significance and great synthetic value of 1,4-diarylbutane-1,4-diols and their derivatives, increasingly considerable attention has been paid to developing effective synthetic methods for chiral 1,4-diarylbutane-1,4-diols. We herein report an efficient asymmetric hydrogenation of 1,4-diaryldiketones catalyzed by a chiral iridium complex bearing f-amphox as ligand, furnishing a series of 1,4-diarylbutane-1,4-diols in excellent yields (up to >99%) with exceptional enantioselectivities (up to >99.9% ee) and diastereoselectivities (up to >100 : 1 dr).

Design and organocatalytic synthesis of spirooxindole–cyclopentene–isoxazole hybrids as novel MDM2–p53 inhibitors

An organocatalytic 1,6-cycloaddition with exclusive α-regioselectivity to synthesize designed spirooxindole–cyclopentene–isoxazole hybrids as novel MDM2–p53 inhibitors.

Access to highly enantioselective and diastereoselective spirooxindole dihydrofuran fused pyrazolones

Access to highly enantioselective and diastereoselective spirooxindole dihydrofuran fused pyrazolones from MBH-carbonates and pyrazole 4,5-diones.

Enantioselective [3+2] annulation of isatin-derived MBH-carbonates and 3-nitroindoles enabled by a bifunctional DMAP-thiourea

Highly enantioselective [3+2] annulation of isatin-derived MBH-carbonates and 3-nitroindoles was achieved by a chiral DMAP-thiourea bifunctional catalyst.

Synthesis of Substituted Isatins from the MBH Adduct of 1,5,6-Trisubstituted Isatins Using (2,4-Dinitrophenyl)hydrazine and K-10 Clay Explored as Protection-Deprotection Chemistry

An interesting synthetic transformation of protection-deprotection chemistry in an isatin molecule is achieved. Morita-Baylis-Hillman (MBH) adduct formation used as protection of the C-3 position in the isatin molecule is reported. C-C bond cleavage in the MBH adduct of isatin with the help of phenylhydrazine and C=N bond cleavage in the phenylhydrazone derivative of isatin with the help of K10 clay are studied systematically and reported as deprotection.

Asymmetric domino 1,6-addition/annulation reaction of 3-cyano-4-alkenyl-2H-chromen-2-ones with isatin-derived MBH carbonates: enantioselective synthesis of 3,3′-cyclopentenylspirooxindoles bearing 2H-chromen-2-ones

An asymmetric domino 1,6-addition/annulation reaction of 3-cyano-4-alkenyl-2H-chromen-2-ones with isatin-derived MBH carbonates was achieved by using a modified cinchona alkaloid as a catalyst.

Phosphine Organocatalysis

The hallmark of nucleophilic phosphine catalysis is the initial nucleophilic addition of a phosphine to an electrophilic starting material, producing a reactive zwitterionic intermediate, generally under mild conditions. In this Review, we classify nucleophilic phosphine catalysis reactions in terms of their electrophilic components. In the majority of cases, these electrophiles possess carbon-carbon multiple bonds: alkenes (section 2), allenes (section 3), alkynes (section 4), and Morita-Baylis-Hillman (MBH) alcohol derivatives (MBHADs; section 5). Within each of these sections, the reactions are compiled based on the nature of the second starting material-nucleophiles, dinucleophiles, electrophiles, and electrophile-nucleophiles. Nucleophilic phosphine catalysis reactions that occur via the initial addition to starting materials that do not possess carbon-carbon multiple bonds are collated in section 6. Although not catalytic in the phosphine, the formation of ylides through the nucleophilic addition of phosphines to carbon-carbon multiple bond-containing compounds is intimately related to the catalysis and is discussed in section 7. Finally, section 8 compiles miscellaneous topics, including annulations of the Hüisgen zwitterion, phosphine-mediated reductions, iminophosphorane organocatalysis, and catalytic variants of classical phosphine oxide-generating reactions.

Multifunctional chiral phosphine-catalyzed [3+2] annulation of Morita-Baylis-Hillman carbonates with cyclopentenones: asymmetric synthesis of 4-oxo-hexahydropentalenes

A multifunctional chiral phosphine-catalyzed enantioselective [3+2] annulation of Morita-Baylis-Hillman carbonates with cyclopentenones provides a direct approach to access functional 4-oxo-1,3a,4,5,6,6a-hexahydropentalene compounds. Moderate to good yields and excellent enantioselectivities (>90% ee) were obtained for a series of substrates under mild reaction conditions.

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.

Catalyst-free [3 + 2] cyclization of dihydroisoquinoline imines and isatin-derived Morita–Baylis–Hillman carbonates via 1,5-electrocyclization: synthesis of tetrahydroisoquinoline-fused spirooxindoles

The incorporation of tetrahydroisoquinoline and spirooxindole frameworks has been achieved.

Recent advances in the annulation of Morita–Baylis–Hillman adducts

In this review, we summarize some of the most recent advances in the construction of cyclic compounds from the annulation of Morita–Baylis–Hillman (MBH) adducts, which have demonstrated their importance by possessing diverse functional groups.

Construction of highly enantioenriched spirocyclopentaneoxindoles containing four consecutive stereocenters via thiourea-catalyzed asymmetric Michael-Henry cascade reactions

The thiourea-catalyzed asymmetric synthesis of highly enantioenriched spirocyclopentaneoxindoles containing chiral amide functional groups using simple 3-substituted oxindoles and nitrovinylacetamide as starting materials was achieved successfully. This protocol features operational simplicity, high atom economy, and high catalytic asymmetry, thus representing a versatile approach to the synthesis of highly enantioenriched spirocyclopentaneoxindoles.

Catalyst-free [3 + 2] cyclization of imines and Morita–Baylis–Hillman carbonates: a general route to tetrahydropyrrolo[2,1-a]isoquinolines and dihydropyrrolo[2,1-a]isoquinolines

A mild and efficient catalyst-free [3 + 2] cyclization of isoquinoline imines and Morita–Baylis–Hillman carbonates has been developed.