Recent Advances in Squaramide‐Catalyzed Asymmetric Mannich Reactions

Hou, Xi‐Qiang; Du, Dan

doi:10.1002/adsc.202000842

Cited by 56 publications

(22 citation statements)

References 187 publications

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“…Due to its atom economy, the increasing popularity of the Mannich reaction has been fueled by the ubiquitous nature of nitrogen‐containing Mannich products in natural and drugs compounds. [ 19 ] At present, although numerous efforts of the two reactions catalyzed by POMs have been developed to overcome drawbacks associated with the classical oxidation of sulfides and Mannich reactions, problems like harsh reaction conditions, reusing and recycling of catalysts, difficulty in products separation still remain concerns. [ 20 ] To the best of our knowledge, the reports about decavanadate‐based transition metal hybrids serving as bifunctional catalysts in selective oxidation of sulfides and construction of C—C bonds have been rarely reported.…”

Section: Background and Originality Contentmentioning

confidence: 99%

Decavanadate‐based Transition Metal Hybrids as Bifunctional Catalysts for Sulfide Oxidation and C—C Bond Construction

Huang

et al. 2021

Chin. J. Chem.

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Main observation and conclusion The development of bifunctional catalysts has drawn much attention in realizing efficient and feasible catalytic systems to meet the diverse demand of potential industrial applications. Design of stable and powerful bifunctional catalysts for various catalysis systems is highly desirable yet largely unmet. Here, three kinds of decavanadate‐based transition metal hybrids (DTMH) (i.e., Co‐DTMH, Ni‐DTMH and Ag‐DTMH) have been successfully synthesized through a pH tuning strategy and further characterized. Specifically, the rare MO5N six‐coordinated transition metal coordination modes have been detected in Co‐DTMH and Ni‐DTMH, while Ag atoms in Ag‐DTMH exhibited three‐ and five‐coordinated geometries with the tuning of specially selected imidazole ligands. Thus‐obtained clusters can serve as powerful bifunctional catalysts for both sulfide oxidation and C—C bond construction. Remarkably, Ag‐DTMH demonstrated excellent heterogeneous bifunctional catalytic properties in the selective oxidation of sulfides and construction of C—C bond (yields up to 99%), which enable successful recycling for three cycles with remained catalytic activities and structure stability. The newly designed decavanadate‐based transition metal hybrids with bifunctional property hold high promise in the practical applications like continuous catalysis or flow bed reactions.

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Section: Background and Originality Contentmentioning

confidence: 99%

Decavanadate‐based Transition Metal Hybrids as Bifunctional Catalysts for Sulfide Oxidation and C—C Bond Construction

Huang

et al. 2021

Chin. J. Chem.

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“…[10] Squaramides have been envisaged as powerful catalysts for a handful of asymmetric organic transformations, including cycloaddition over the past decade. [11,12] Cycloaddition is a very fundamental approach to construct carbo-and heterocycles. Five and Six-membered rings are omnipresent in large numbers of natural products, bioactive and pharmaceutical molecules.…”

Section: Introductionmentioning

confidence: 99%

“…Squaramides have been envisaged as powerful catalysts for a handful of asymmetric organic transformations, including cycloaddition over the past decade [11,12] . Cycloaddition is a very fundamental approach to construct carbo‐ and heterocycles.…”

Section: Introductionmentioning

confidence: 99%

Squaramide Catalyzed Asymmetric Synthesis of Five‐ and Six‐Membered Rings

Biswas¹,

Ghosh

Shankhdhar

et al. 2021

Asian J Org Chem

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Chiral analogues of squaramides have been fruitful in organocatalyzed asymmetric reactions over last decade. Alongside other H-bonding catalysts like ureas, thioureas: squaramides have been proved to be efficient asymmetric catalysts for the formation of acyclic and cyclic chiral molecules. A wide range of cyclic molecules bearing multiple functionalities and stereocenters have been synthesized by using several bifunctional squaramides as catalysts. These catalysts perform as base utilizing basic N atom in their chiral extension and help in stereoinduction by forming H-bonds with suitable H-bond acceptors. The present review focuses on assembling recent progresses of asymmetric synthesis of five and six membered rings promoted by squaramides. A handful of articles have been published by several research groups documenting asymmetric construction of five-and six-membered rings as part of interesting and complex molecular architectures. Different methodologies like conventional and formal cycloadditions or cascade reactions have been engineered through the assistance of chiral squaramides to fabricate the carbo-and heterocycles. This review also includes dual and cooperative catalytic system in which squaramide is one of the catalysts.

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“…Over the years, the asymmetric catalytic Mannich reaction of ketimines (Scheme 1) has been of significant interest to synthetic and medicinal chemists as a way to access synthetically versatile compounds bearing an α-tertiary amine stereogenic center (selected reviews; [13][14][15][16][17][18][19][20][21][22][23]). It is because optically pure chiral α-tertiary amines are a key structural motif found in a large number of biologically relevant molecules and natural products (Figure 1) [24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Catalytic Ketimine Mannich Reactions and Related Transformations

Reep

Jarvis

et al. 2021

Catalysts

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The catalytic enantioselective ketimine Mannich and its related reactions provide direct access to chiral building blocks bearing an α-tertiary amine stereogenic center, a ubiquitous structural motif in nature. Although ketimines are often viewed as challenging electrophiles, various approaches/strategies to circumvent or overcome the adverse properties of ketimines have been developed for these transformations. This review showcases the selected examples that highlight the benefits and utilities of various ketimines and remaining challenges associated with them in the context of Mannich, allylation, and aza-Morita–Baylis–Hillman reactions as well as their variants.

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Recent Advances in Squaramide‐Catalyzed Asymmetric Mannich Reactions

Cited by 56 publications

References 187 publications

Decavanadate‐based Transition Metal Hybrids as Bifunctional Catalysts for Sulfide Oxidation and C—C Bond Construction

Decavanadate‐based Transition Metal Hybrids as Bifunctional Catalysts for Sulfide Oxidation and C—C Bond Construction

Squaramide Catalyzed Asymmetric Synthesis of Five‐ and Six‐Membered Rings

Asymmetric Catalytic Ketimine Mannich Reactions and Related Transformations

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