An Assembly of Pyrano[3,2‐b]indol‐2‐ones via NHC‐Catalyzed [3 + 3] Annulation of Indolin‐3‐ones with Ynals^†

Chinese Journal of Chemistry, Год журнала: 2024, Номер 42(13), С. 1487 - 1492

Опубликована: Март 10, 2024

Comprehensive Summary We report herein an unprecedented N ‐heterocyclic carbene‐catalyzed formal [3 + 3] annulation of ynals with ‐Ts indolin‐3‐ones under the oxidation condition affording functionalized pyrano[3,2‐ b ]indol‐2‐ones. The alkynyl acylazoliums via combination a carbene in presence oxidate proved to be important intermediates for success this transformation. This method features broad substrate scope and mild conditions, including axially chiral skeletons suitable substitutions.

Язык: Английский

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Enantioselective Cascade Annulation of 1,2,3-Triazoles and Enals Enabled by Sequential Rhodium and Oxidative NHC Catalysis Involving Cleavage, Migration, and Cyclization

Organic Letters, Год журнала: 2025, Номер unknown

Опубликована: Фев. 28, 2025

The in situ-generated pyrrolin-3-ones serve as novel and versatile synthons, being employed intermediates for the efficient production of pyrrole-fused lactones with high yield excellent enantioselectivity. Herein, we introduce emerging rhodium oxidative N-heterocyclic carbene relay catalysis that enables a highly enantioselective cascade annulation between easily available 1,2,3-triazoles enals. In this proof-of-concept study, engage α,β-unsaturated acylazolium generated from enals via catalysis.

Язык: Английский

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Kinetic Resolution of Amino Acids by Phosphine Oxide Catalyzed Enantioselective Esterification

Research Square (Research Square), Год журнала: 2025, Номер unknown

Опубликована: Май 7, 2025

The first highly efficient kinetic resolution (KR) of racemic amino acids with L-pyroglutaminol as an esterification reagent was reported through a novel phosphine oxide organocatalyst catalyzed under mild conditions, which provides wide range chiral esters and recovered excellent stereoselectivities (s > 1057). catalyst demonstrated stereocontrol catalytic activity, presumably benefited from intimate double H-bonding interaction between the pyroglutaminol core catalyst. Chiral find applications versatile building blocks in synthesis functional molecules, source information asymmetric tools to expand explore function native biological machinery.^1–8 Therefore, represent class valuable indispensable compounds whose stereoselective is major objective within synthetic chemists biologists.^9–10 To best our knowledge, array effective strategies for construction have been developed, such hydrogenation nucleophilic addition imines^11–18, enantioselective carbene insertion into N-H bonds amines or amides^19–23, photobiocatalytic cross-coupling^24–27, stereocontrolled 1,3-nitrogen migration carboxylic acids²⁸. However, identifying specific reaction not always easy task. An alternative well-established strategy relies on KR mixture (Fig. 1a).^29–31 stands out one most practical straightforward obtaining enantioenriched molecules recovering starting materials, effectively allowing access both enantiomers single enantiomer Numerous processes developed that reliably deliver enantiopure compounds, including alcohols^32–36, monohydrosilanes³⁷, organoperoxides³⁸, alkynes^39–40, sulfonyl ketones⁴¹, amines⁴², imines⁴³, sulfoximines^44–45, aldehydes⁴⁶, phosphindane oxides^47–48, heterocyclic compounds^49–52. Despite this significant progress field, remains challenging task has rarely explored.^53–57

Язык: Английский

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Diastereo- and Enantioselective Chemodivergent Three-Component Cascade Reactions via Gold and Carbene Sequential Catalysis

ACS Catalysis, Год журнала: 2024, Номер 14(12), С. 9275 - 9282

Опубликована: Июнь 4, 2024

This study investigates the feasibility and inherent benefits of combining transition-metal- organoasymmetric-catalyzed reactions in one pot. The reported transformation features Au-catalyzed tandem hydration–oxacyclization NHC-catalyzed enantioselective annulation, effectively converting simple skipped diynones, water, enals into highly diastereo- enantioenriched fused heterocycles. Furthermore, chemoselectivity controlled by base is particularly noteworthy, enabling facile access to ε-lactones or spiro heterocycles from same set starting materials.

Язык: Английский

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NHC-Catalyzed Reaction of Aldehydes for C(sp2)–O Bond Formation

Catalysts, Год журнала: 2024, Номер 14(4), С. 219 - 219

Опубликована: Март 22, 2024

In the past few decades, N-heterocyclic carbenes (NHCs) have opened new field of organocatalysis in synthetic organic chemistry. This review highlights dramatic progress NHC-catalyzed C–O bond formation based on activation aldehyde C(sp2)–H bonds. The oxidative and redox transformations for synthesis various molecules with structural diversity complexity are summarized. Furthermore, methods strategies NHC catalysis emerging continuously; thus, cooperative Brønsted acid, hydrogen-bonding catalyst, transition-metal photocatalyst also described.

Язык: Английский

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