Brønsted Acid‐Catalysed Dehydrative Substitution Reactions of Alcohols

Chemistry - A European Journal, Journal Year: 2020, Volume and Issue: 27(1), P. 106 - 120

Published: June 3, 2020

Abstract The direct, catalytic dehydrative substitution of alcohols is a challenging, yet highly desirable process in the development more sustainable approaches to organic chemistry. This review outlines recent advances Brønsted acid‐catalysed reactions for C−C, C−O, C−N and C−S bond formation. wide range processes that are now accessible using simple as formal electrophile highlighted, while current limitations therefore possible future directions research also discussed.

Language: Английский

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Development of Asymmetric Propargylic Substitution Reactions Using Transition Metal Catalysts

Chemistry Letters, Journal Year: 2021, Volume and Issue: 50(6), P. 1282 - 1288

Published: March 31, 2021

This highlight review overviews our recent advances on enantioselective propargylic substitution reactions catalyzed by transition metal complexes including cooperative and hybrid catalysts for the last 15 years.

Language: Английский

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Enantioconvergent Substitution Reactions of Racemic Electrophiles by Organocatalysis

Chemistry - A European Journal, Journal Year: 2021, Volume and Issue: 27(40), P. 10215 - 10225

Published: March 30, 2021

Over the past decades, development of enantioselective catalysis using organocatalysts has evolved into an active research field and a number transformations have been established. However, despite their being highly desirable process for synthesis organic molecules in enantioenriched form, enantioconvergent substitution reactions racemic electrophiles still present several challenges. Although intrinsic difficulties catalytic stereocontrol abound due to initial chiral information electrophiles, recent years, mechanistically diverse processes intensively investigated organocatalysis. This Minireview focuses on achievements organocatalysts. The contents are classified basis mechanistic types processes.

Language: Английский

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A Reverse Approach to the Total Synthesis of Halichondrin B

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(24), P. 9267 - 9276

Published: June 9, 2021

A new strategy is described for the total synthesis of halichondrin B featuring reversal sequential construction a number its cyclic ethers from classical approach by instead forming C–O bonds first followed C–C bond formation. Employing Nicholas reaction to generate linear as precursors and other members eribulin families compounds, this novel provides opportunities development improved syntheses these complex valuable compounds. In Article, we report defined fragments I, MN, EFG, A. Fragments I MN were then coupled elaborated advanced intermediate IJKLMN, which was joined with fragment EFG afford, after appropriate elaboration macrolactonization, more polycyclic EFGHIJKLMN. Elaboration latter coupling further functionalization completed through short convergent pathway.

Language: Английский

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Design Approaches That Utilize Ionic Interactions to Control Selectivity in Transition Metal Catalysis

Chemical Reviews, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 28, 2025

The attractive force between two oppositely charged ions can constitute a powerful design tool in selective catalysis. Enzymes make extensive use of ionic interactions alongside variety other noncovalent interactions; recent years have seen synthetic chemists begin to seriously explore these catalyst designs that also incorporate reactive transition metal. In isolation, single interaction exhibits low directionality, but many successful systems they exist additional which provide high degree organization at the selectivity-determining state. Even situations with key interaction, directionality is not always detrimental, and even be advantageous, conferring generality catalyst. This Review explores approaches utilize control selectivity metal It divided into halves: first, occurs outer sphere complex, using ligand or bound an anion; second, bears formal charge, associated counterion.

Language: Английский

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Recent Advances in First-Row Transition Metal/Chiral Phosphoric Acid Combined Catalysis

Topics in Current Chemistry, Journal Year: 2019, Volume and Issue: 377(5)

Published: Aug. 28, 2019

Language: Английский

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Divergent Construction of Macrocyclic Alkynes via Catalytic Metal Carbene C(sp²)–H Insertion and the Buchner Reaction

ACS Catalysis, Journal Year: 2019, Volume and Issue: 9(12), P. 10773 - 10779

Published: Oct. 28, 2019

A catalytic macrocyclization reaction of alkyne embodied diazoacetates through metal carbene intermediates is described. This method provides a variety functionalized 13- to 20-membered cycloalkynes in synthetically useful yields under mild conditions. In the presence copper-catalyst, C(sp2)–H insertion takes place dominantly with tethered nucleophilic aniline species. Alternatively, Buchner aryl group occurs selectively when catalyzed by dirhodium complex. Notably, this only example using C–H functionalization and reactions for direct selective construction cycloalkyne frameworks.

Language: Английский

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Chiral Brønsted Acid Catalyzed Enantioconvergent Propargylic Substitution Reaction of Racemic Secondary Propargylic Alcohols with Thiols

Chemistry - A European Journal, Journal Year: 2020, Volume and Issue: 26(49), P. 11124 - 11128

Published: April 10, 2020

Abstract Despite the significant progress of enantioselective reaction using chiral catalysts, nucleophilic substitution at sp 3 ‐hybridized carbon atom a racemic electrophile has not been largely explored. Herein, we report enantioconvergent propargylic alcohols with thiols bis‐phosphoric acid as Brønsted catalyst. The products were formed in high yields enantioselectivities most cases. cation‐stabilizing effect sulfur functional group introduced alkynyl terminus is key to achieving efficient process, which information originating from only stereogenic center but also contact ion pair completely eliminated present system.

Language: Английский

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Mechanisms and Stereoselectivities of NHC‐Catalyzed [3 + 4] Cycloaddition Reaction between Isatin‐Derived Enal and N‐(ortho‐Chloromethyl)aryl Amide

European Journal of Organic Chemistry, Journal Year: 2019, Volume and Issue: 2019(19), P. 2989 - 2997

Published: May 3, 2019

Possible mechanisms and origins of stereoselectivity N‐heterocyclic carbene (NHC) promoted spirobenzazepinone formation from the annulation an isatin‐derived enal N‐(ortho‐chloromethyl)aryl amide have been investigated computationally. DFT results (M06–2X) suggest that preferred mechanism consists six steps: The nucleophilic coupling NHC catalyst was considered as first reaction step ( I ), followed by generation Breslow intermediate through a HCO 3 – assisted proton transfer event II ). next is addition to generating acyl azolium III Then proceeds successive intramolecular cycloaddition IV H 2 O‐mediated 1,3‐proton V ) elimination VI affording [3+4] product. Step plays pivotal role in determining leads experimentally observed S ‐configuration account for experimental observations. Global reactivity index analysis has also conducted identify catalyst.

Language: Английский

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Catalytic Enantioselective Synthesis of 1,4-Benzodioxepines

Organic Letters, Journal Year: 2019, Volume and Issue: 22(1), P. 249 - 252

Published: Dec. 16, 2019

An efficient organocatalytic enantioselective synthesis of chiral 1,4-benzodioxepines is described. By proper incorporation an intramolecular oxetane desymmetrization process, a range benzylic alcohols bearing internal reacted in the presence suitable phosphoric acid catalyst to form with high enantioselectivity. This process provides new catalytic asymmetric example direct seven-membered heterocycles good stereocontrol.

Language: Английский

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