Zinc‐Catalyzed Enantioselective Formal (3+2) Cycloadditions of Bicyclobutanes with Imines: Catalytic Asymmetric Synthesis of Azabicyclo[2.1.1]hexanes

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(48)

Published: Sept. 2, 2024

Abstract The cycloaddition reaction involving bicyclo[1.1.0]butanes (BCBs) offers a versatile and efficient synthetic platform for producing C(sp 3 )‐rich rigid bridged ring scaffolds, which act as phenyl bioisosteres. However, there is scarcity of catalytic asymmetric cycloadditions BCBs to fulfill the need enantioenriched saturated bicycles in drug design development. In this study, an synthesis valuable azabicyclo[2.1.1]hexanes (aza‐BCHs) by enantioselective zinc‐catalyzed (3+2) with imines reported. proceeds effectively novel type BCB that incorporates 2‐acyl imidazole group diverse array alkynyl‐ aryl‐substituted imines. target aza‐BCHs, consist α‐chiral amine fragments two quaternary carbon centers, are efficiently synthesized up 94 % 96.5:3.5 er under mild conditions. Experimental computational studies reveal follows concerted nucleophilic ring‐opening mechanism This distinct from previous on Lewis acid‐catalyzed BCBs.

Language: Английский

---

Copper-Catalyzed Enantioselective [4π + 2σ] Cycloaddition of Bicyclobutanes with Nitrones

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 25, 2024

The selective construction of bridged bicyclic scaffolds has garnered increasing attention because their extensive use as saturated bioisosteres arene in pharmaceutical industry. However, sharp contrast to racemic counterparts, assembling chiral structures an enantioselective and regioselective manner remains challenging. Herein, we describe our protocol for constructing 2-oxa-3-azabicyclo[3.1.1]heptanes (BCHeps) by [4π + 2σ] cycloadditions bicyclo[1.1.0]butanes (BCBs) nitrones taking advantage a copper(II) complex Lewis acid catalyst. This method features mild conditions, good functional group tolerance, high yield (up 99%), excellent enantioselectivity 99% ee). Density theory (DFT) calculation elucidates the origin reaction's mechanism BCB activation Cu(II) complex.

Language: Английский

---

Formal [2σ + 2σ]-Cycloaddition of Aziridines with Bicyclo[1.1.0]butanes: Access to Enantiopure 2-Azabicyclo[3.1.1]heptane Derivatives

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 19, 2024

Saturated nitrogen heterocycles are among the most significant structural components in small-molecule pharmaceuticals. Herein, a protocol for construction of enantiopure 2-azabicyclo[3.1.1]heptane derivatives by stereospecific intermolecular formal cycloaddition aziridines with bicyclo[1.1.0]butanes is described. The reaction run using B(C

Language: Английский

---

Enantioselective synthesis of 2-substituted bicyclo[1.1.1]pentanes via sequential asymmetric imine addition of bicyclo[1.1.0]butanes and skeletal editing

Nature Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 28, 2025

Language: Английский

---

Enantioselective Synthesis of Tetrahydro-1H-1,3-methanocarbazoles by Formal (3 + 3)-Cycloaddition Using Bicyclo[1.1.0]butanes

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 28, 2025

Asymmetric synthesis presents many challenges, with the selective formation of chiral bridged polyheterocycles being a notable example. Cycloadditions using bicyclo[1.1.0]butanes (BCB) offer promising solution along those lines, yet, despite significant advances in that emerging area, asymmetric control has remained limited thus far. Here, we describe an organocatalytic, enantioselective formal (3 + 3)-cycloaddition BCBs 1H-indol-3-yl((hetero)aryl)methanol derivatives. This approach enables rapid and efficient tetrahydro-1H-1,3-methanocarbazole derivatives (34 examples) from readily available starting materials, very good stereochemical (up to 98:2 er). Successful scale-up experiments product modification demonstrated potential this methodology. Control DFT calculations provide insights into mechanistic pathway.

Language: Английский

---

Palladium-catalyzed enantioselective [2σ + 2π] cycloadditions of vinyl-carbonyl-bicyclo[1.1.0]butanes with arylidenemalononitriles

Chinese Chemical Letters, Journal Year: 2025, Volume and Issue: unknown, P. 111072 - 111072

Published: March 1, 2025

Language: Английский

---

Silver-mediated formal [4π + 2σ] cycloaddition reactions of bicyclobutanes with nitrile imines: access to 2,3-diazobicyclo[3.1.1]heptenes

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

Published: Jan. 1, 2025

We disclose a method for silver-enabled formal [4π + 2 σ ] cycloaddition reactions between bicyclobutanes and nitrile imines (generated from hydrazonyl chlorides) to furnish diverse array of 2,3-diazo-BCHepes.

Language: Английский

---

Divergent Enantioselective Access to Diverse Chiral Compounds from Bicyclo[1.1.0]butanes and α,β-Unsaturated Ketones under Catalyst Control

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 30, 2024

Achieving structural and stereogenic diversity from the same starting materials remains a fundamental challenge in organic synthesis, requiring precise control over selectivity. Here, we report divergent catalytic methods that selectively yield either cycloaddition or addition/elimination products bicyclo[1.1.0]butanes α,β-unsaturated ketones. By employing chiral Lewis acid Brønsted catalysts, achieved excellent regio-, diastereo-, enantioselectivity across all three distinct transformations, affording diverse array of synthetically valuable bicyclo[2.1.1]hexanes cyclobutenes. The outcomes are controlled by differential activation substrates specific catalyst with reaction conditions dictating pathway This strategy demonstrates power catalysis creating molecular complexity diversity, offering tool for synthesis enantioenriched building blocks.

Language: Английский

---

Ring Expansion toward Fused Diazabicyclo[3.1.1]heptanes through Lewis Acid Catalyzed Highly Selective C−C/C−N Bond Cross‐Exchange Reaction between Bicyclobutanes and Diaziridines

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 13, 2024

Abstract The synthesis of bicyclic scaffolds has garnered considerable interest in drug discovery because their ability to mimic benzene bioisosteres. Herein, we introduce a new approach that utilizes Lewis acid (Sc(OTf) 3 )‐catalyzed σ‐bond cross‐exchange reaction between the C−C bond bicyclobutanes and C−N diaziridines produce multifunctionalized medicinally interesting azabicyclo[3.1.1]heptane derivatives. proceeds well with different broad range aryl‐ as alkenyl‐, but also alkyl‐substituted (up 98 % yield). Conducting scale‐up experiment exploring synthetic transformations cycloadducts emphasized practical application synthesis. Furthermore, zinc‐based chiral catalytic system was developed for enantioselective version this 96 ee ).

Language: Английский

---

Enantioselective Dearomative [2π + 2σ] Photocycloaddition of Naphthalene Derivatives with Bicyclo[1.1.0]butanes Enabled by Gd(III) Catalysis

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: March 28, 2025

The cycloaddition reactions of bicyclo[1.1.0]butanes with alkenes, imines, nitrones, or aziridines have served as an efficient platform to create conformationally restricted saturated bicyclic scaffolds. However, the use readily available aromatics in such reactions, especially asymmetric manner, remains underexplored. Herein, we report a highly regio- and enantioselective dearomative [2π + 2σ] photocycloaddition reaction between naphthalene derivatives bicyclo[1.1.0]butanes, enabled by Gd(III) catalysis. Bicyclo[1.1.0]butanes naphthalenes adorned diverse array functional groups are well-tolerated under mild conditions, affording enantioenriched pharmaceutically important bicyclo[2.1.1]hexanes 30–96% yields 81–93% ee 12:1 → >20:1 rr. synthetic versatility this is further demonstrated facile removal directing group derivatizations dearomatized product. UV–vis absorption spectroscopy studies suggest involvement excited species process.

Language: Английский

---