Regioselectivity Switch in Palladium‐Catalyzed Allenylic Cycloadditions of Allenic Esters: [4+1] or [4+3] Cycloaddition/Cross‐Coupling

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(14), P. 4710 - 4713

Published: Feb. 11, 2019

Abstract The first Pd‐catalyzed asymmetric allenylic [4+1] cycloaddition was successfully developed. Alternatively, tuning the Pd catalyst switched reactivity toward an unprecedented [4+3] cycloaddition/cross‐coupling. Ligands play a vital role in controlling reaction pathway, allowing highly selective access to different products from identical substrates. Biological evaluation of obtained compounds led discovery new antitumor targets. A possible mechanism is proposed, suggesting two interesting catalytic cycles for with palladium‐butadienyls. This study also demonstrated potential and utility allenic esters as 1,4‐biselectrophiles C 4 synthons participating reactions.

Language: Английский

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Gaussian Process Regression for Minimum Energy Path Optimization and Transition State Search

The Journal of Physical Chemistry A, Journal Year: 2019, Volume and Issue: 123(44), P. 9600 - 9611

Published: Oct. 16, 2019

We implemented a gradient-based algorithm for finding minimum energy paths (MEPs) using Gaussian process regression (GPR). A subsequent search transition states can be performed very fast. describe the in detail and compare its performance to nudged elastic band (NEB) method 27 test systems. Additionally, three different possibilities an initial guess of path are evaluated. found new optimizer considerably decrease number required gradient evaluations.

Language: Английский

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Asymmetric Synthesis of Isoxazol-5-ones and Isoxazolidin-5-ones

Synthesis, Journal Year: 2020, Volume and Issue: 53(01), P. 107 - 122

Published: Oct. 12, 2020

Abstract Isoxazol-5-ones and isoxazolidin-5-ones represent two important classes of heterocycles, with several applications as bioactive compounds versatile building blocks for further transformations. Unlike the parent aromatic isoxazoles, presence one or stereocenters in ring renders their asymmetric construction particularly important. In this review, starting from description general features differences between these related compound families, we present an overview on most enantioselective synthesis strategies to access heterocycles. Both chiral metal catalysts organocatalysts have recently been successfully employed task some promising approaches will be discussed. 1 Introduction 2 Nucleophiles 2.1 C-Nucleophiles 2.2 N-Nucleophiles 2.3 Cyclization Processes 3 Asymmetric Construction Isoxazolidin-5-ones 3.1 Enantioselective α-Functionalizations 4 Arylideneisoxazol-5-ones Conjugated Addition 5 Conclusions

Language: Английский

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Two-Fold Reduction of Dibenzo[a,e]cyclooctatetraene with Group 1 Metals: From Lithium to Cesium

Organometallics, Journal Year: 2020, Volume and Issue: 39(24), P. 4688 - 4695

Published: Dec. 14, 2020

Chemical reduction of sym-dibenzo[a,e]cyclooctatetraene (DBCOT, 1) has been investigated using group 1 metals ranging from Li to Cs as the reducing agents. With all alkali metals, DBCOT readily undergoes a 2-fold afford doubly reduced DBCOT2– (12–) anion. Seven products 12– with different alkali-metal counterions have isolated and fully characterized. Their X-ray diffraction structural analyses reveal ligand core planarization upon addition two electrons well versatility in coordination. The negative charge localization at central eight-membered ring identified by theoretical calculations is consistent crystallographic NMR spectroscopic results. A broad range solid-state arrangements resulting stems metal binding patterns secondary interactions involving coordinating agents used for crystallization (THF vs 18-crown-6 [2.2.2]cryptand). This family salts provides useful reagents metathesis reactions that can be preparation various transition-metal or lanthanide-based organometallic complexes.

Language: Английский

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Regioselective and asymmetric allylic alkylation of vinyl epoxides for the construction of allylic alcohols via synergistic catalysis

Science China Chemistry, Journal Year: 2023, Volume and Issue: 67(2), P. 542 - 550

Published: Nov. 17, 2023

Language: Английский

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