Synthesis of Metallocene Analogues of the Phenethylamine and Tetrahydroisoquinoline Scaffolds via Regioselective Ring Opening of 2‐Aryl‐<i>N</i>‐sulfonyl Aziridines

González‐Pelayo, Silvia; Bernardo, Olaya; Borge, Javier; López, Luís A.

doi:10.1002/adsc.202001210

Cited by 7 publications

(6 citation statements)

References 46 publications

(3 reference statements)

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“…Therefore, soluble Ziegler–Natta or homogeneous metallocene single-site catalyst can be used to synthesis new polymers without the need to remove the catalyst residues from the final polymer product. The activities of soluble catalysts are very encouraging for commercial purposes, but the kinetics behind these catalysts system have not been investigated extensively [ 14 , 15 , 16 , 17 ].…”

Section: Introductionmentioning

confidence: 99%

Kinetic and Thermal Study of Ethylene and Propylene Homo Polymerization Catalyzed by ansa-Zirconocene Activated with Alkylaluminum/Borate: Effects of Alkylaluminum on Polymerization Kinetics and Polymer Structure

et al. 2021

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The kinetics of ethylene and propylene polymerization catalyzed by homogeneous metallocene were investigated using 2-thiophenecarbonyl chloride followed by quenched-flow methods. The studied metallocene catalysts are: rac-Me2Si(2-Me-4-Ph-Ind)2ZrCl2 (Mt-I), rac-Et(Ind)2ZrCl2 (Mt-II) activated with ([Me2NPh][B(C6F5)4] (Borate-I), [Ph3C][B(C6F5)4] (Borate-II), and were co-catalyzed with different molar ratios of alkylaluminum such as triethylaluminium (TEA) and triisobutylaluminium (TIBA). The change in molecular weight, molecular weight distribution, microstructure and thermal properties of the synthesized polymer are discussed in detail. Interestingly, both Mt-I and Mt-II showed high activity in polyethylene with productivities between 3.17 × 106 g/molMt·h to 5.06 × 106 g/molMt·h, activities were very close to each other with 100% TIBA, but Mt-II/borate-II became more active when TEA was more than 50% in cocatalyst. Similarly, Polypropylene showed the highest activity of 11.07 106 g /molMt·h with Mt-I/Borate-I/TIBA. The effects of alkylaluminum on PE molecular weight were much more complicated; MWD curve changed from mono-modal in Mt-I/borate-I/TIBA to bimodal type when TIBA was replaced by different amounts of TEA. In PE, the active center fractions [C*]/[Zr] of Mt-I/borate were higher than that of Mt-II/borate and average chain propagation rate constant (kp) value slightly decreased with the increase of TEA/TIBA ratio, but the Mt-II/borate systems showed higher kp 1007 kp (L/mol·s). In PP, the Mt-I/borate presented much higher [C*]/[Zr] and kp value than the Mt-II. This work also extend to investigate the mechanistic features of zirconocenes catalyzed olefin polymerizations that addressed the largely unknown issues in zirconocenes in the distribution of the catalyst, between species involved in polymer chain growth and dormant state. In both metallocene systems, chain transfer with alkylaluminum is the dominant way of chain termination. To understand the mechanism of cocatalyst effects on PE Mw and (MWD), the unsaturated chain ends formed via β-H transfer have been investigated by 1H NMR analysis.

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Section: Introductionmentioning

confidence: 99%

Kinetic and Thermal Study of Ethylene and Propylene Homo Polymerization Catalyzed by ansa-Zirconocene Activated with Alkylaluminum/Borate: Effects of Alkylaluminum on Polymerization Kinetics and Polymer Structure

et al. 2021

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“…Finally, considering the utility of aziridine derivatives as synthetic intermediates, [20] and our current interest in the ring opening of activated aziridines, [21] we postulated that compound 8 a could serve as a convenient precursor for generating the previously unreported 2‐ferrocenyl‐1‐tosylaziridine. In this context, treatment of ferrocene derivative 8 a with an excess of NaH in THF, followed by quenching with water, resulted in the regioselective formation of the hydroxyamination product 9 a with an acceptable yield (Scheme 8).…”

Section: Resultsmentioning

confidence: 99%

Catalyst‐Free Regioselective 1,2‐Diheterofunctionalization of Vinylferrocene

García‐Martínez,

Crespo,

González

et al. 2023

Eur J Inorg Chem

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In this study, we report a catalyst‐free aminohalogenation process applied to vinylferrocene, employing N‐halosuccinimides (NXS; X=Cl, Br, I) as dual nitrogen and halogen sources. This 1,2‐diheterofunctionalization reaction takes place with complete regioselectivity, wherein the terminal carbon atom of the vinyl group selectively reacts with the electrophilic halogenating reagent, resulting in the formation of a cationic intermediate, which is subsequently captured by the succinimide anion. The structure of the key cationic intermediate was studied using theoretical methods. This intermediate can react with alternative nucleophiles, enabling a three‐component strategy for the synthesis of novel 1,2‐diheterofunctionalized ferrocene derivatives.

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“…In 2021, González-Pelayo and coworkers accomplished the construction of a set of metallocene analogs of the relevant tetrahydroisoquinoline motif 45 by TfOH-catalyzed three-component reactions of 2-aryl-N-sulfonyl aziridines 42 with ferrocene (or ruthenocene) 43 and formaldehyde 44 (►Scheme 11). 76 Initially, the amino-functionalized metallocene derivatives were formed from a regioselective ring opening of the aziridine. Later, an intermolecular Pictet-Spengler cyclization of the formed intermediate and formaldehyde led to target products.…”

Section: Three-component Pictet-spengler Cyclization-based Domino Rea...mentioning

confidence: 99%

Pictet–Spengler-Based Multicomponent Domino Reactions to Construct Polyheterocycles

Hu,

Huang,

Feng

2023

Pharmaceutical Fronts

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The Pictet–Spengler reaction is one of the important methodological arsenals in synthetic and medicinal chemistry, acting as an amenable tool for preparing tetrahydroisoquinoline, tetrahydro-β-carbolines, polycyclic skeletons, and value-added products. More than 100 years after its initial discovery, the Pictet–Spengler reaction's response has not withdrawn from the stage, but it has once again become the focus of attention with new features. The review summarizes recent advances in Pictet–Spengler-based multicomponent reactions from 2007 to 2022, including three-component and four-component Pictet–Spengler cyclization reactions in the presence of metal catalysts, organocatalysts, biological enzyme catalysts, and so on. These Pictet–Spengler-based multicomponent protocols provide an atom-/step economic approach for the synthesis of a library of new chemical entities.

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Synthesis of Metallocene Analogues of the Phenethylamine and Tetrahydroisoquinoline Scaffolds via Regioselective Ring Opening of 2‐Aryl‐N‐sulfonyl Aziridines

Cited by 7 publications

References 46 publications

Kinetic and Thermal Study of Ethylene and Propylene Homo Polymerization Catalyzed by ansa-Zirconocene Activated with Alkylaluminum/Borate: Effects of Alkylaluminum on Polymerization Kinetics and Polymer Structure

Kinetic and Thermal Study of Ethylene and Propylene Homo Polymerization Catalyzed by ansa-Zirconocene Activated with Alkylaluminum/Borate: Effects of Alkylaluminum on Polymerization Kinetics and Polymer Structure

Catalyst‐Free Regioselective 1,2‐Diheterofunctionalization of Vinylferrocene

Pictet–Spengler-Based Multicomponent Domino Reactions to Construct Polyheterocycles

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