Cobalt‐Catalyzed Decarboxylative Allylations: Development and Mechanistic Studies

Chemistry - A European Journal, Journal Year: 2023, Volume and Issue: 29(58)

Published: July 19, 2023

In recent years, there has been a concerted drive to develop methods that are greener and more sustainable. Being an earth-abundant transition metal, cobalt offers attractive substitute for commonly employed precious metal catalysts, though reactions engaging still less developed. Herein, we report method achieve the decarboxylative allylation of nitrophenyl alkanes, nitroalkanes, ketones employing cobalt. The reaction allows formation various substituted allylated products in moderate-excellent yields with broad scope. Additionally, synthetic potential methodology is demonstrated by transformation into versatile heterocyclic motifs. Mechanistic studies revealed situ activation Co(II)/dppBz precatalyst carboxylate salt generate Co(I)-species, which presumed be active catalyst.

Language: Английский

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Pd-Catalyzed regio- and stereoselective allylic substitution of vinylethylene carbonates with 1,2,4-triazoles

Organic & Biomolecular Chemistry, Journal Year: 2022, Volume and Issue: 20(33), P. 6532 - 6536

Published: Jan. 1, 2022

Pd-Catalyzed allylic substitution of vinylethylene carbonates with 1,2,4-triazoles has been developed to produce N 1 -allylated in high yields excellent regio- and stereoselectivities.

Language: Английский

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Base-Promoted Decarboxylative Annulation of Methyl 2-(2-Bromophenyl)acetates and Ynones to Access Benzoxepines

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 88(5), P. 3079 - 3088

Published: Feb. 17, 2023

A simple and efficient base-mediated decarboxylative annulation of ynones with methyl 2-(2-bromophenyl)acetates has been developed. broad range benzoxepines were prepared a substrate scope high regioselectivity in moderate to excellent yields under transition-metal-free conditions. This method proceeds through tandem [2 + 4] annulation, ring-opening reaction, the intramolecular nucleophilic aromatic substitution reaction. Additionally, key intermediates successfully obtained characterized unambiguously by single-crystal X-ray crystallography, which could favorably support mechanism. Furthermore, gram-scale reaction synthetic applications for further functionalization are also studied.

Language: Английский

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Highly Regio- and Diastereoselective Synthesis of 6,7-Dihydro-4H-furo[3,4-c]pyran Derivatives through Pd-Catalyzed Formal (3 + 3) Allylic Cycloaddition of 2-Butene-1,4-diols with 2-(1-Alkynyl)-2-alken-1-ones

Organic Letters, Journal Year: 2024, Volume and Issue: 26(10), P. 2018 - 2022

Published: Feb. 29, 2024

A highly efficient synthesis of 7-vinyl-6,7-dihydro-4H-furo[3,4-c]pyran derivatives from 2-butene-1,4-diols and 2-(1-alkynyl)-2-alken-1-ones has been achieved with high regio- diastereoselectivity (dr > 20:1) by Pd-catalyzed tandem heterocyclization/cross-coupling. The π-allyl palladium species Int II generated 2-butene-1,4-diol direct cleavage the C–OH bond is key to success in this formal (3 + 3) cycloaddition reaction.

Language: Английский

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Rh(III)-Catalyzed C–H Allylation of Aromatic Ketoximes with Vinylaziridines

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(8), P. 5764 - 5777

Published: April 5, 2024

The Rh(III)-catalyzed reaction of aromatic ketoximes with 2-vinylaziridines affords ortho-allylation products the phenyl rings in moderate to excellent yields. requires 0.5 equiv NaOAc as a base and occurs under mild conditions. protocol exhibits ortho-monoallylation selectivity, wide scope substrates, good compatibility functional groups.

Language: Английский

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Cobalt‐Catalyzed Allylic Alkylation at sp3‐Carbon Centers

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(47)

Published: June 13, 2024

Abstract The rising demand and financial costs of noble transition metal catalysts have emphasized the need for sustainable catalytic approaches. Over past few years, base‐metal emerged as ideal candidates to replace their noble‐metal counterparts because abundance easiness handling. Despite significant advancements achieved with precious metals, earth‐abundant cobalt efficient alternatives allylic substitution reactions. In this review, alkylations at sp 3 ‐carbon centers mediated by will be discussed, a special focus on mechanistic features, scope, limitations.

Language: Английский

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Dual Reactivity Mode of Vinyl Ethylene Carbonates with Anilines: A Catalyst-Controlled Chemodivergent Entry to N-Heterocycles and the Observation of Unusual Competing Pathways

Published: June 25, 2024

A unique catalyst-controlled chemodivergent strategy to access 2-vinyl indolines and indole-2-acetates by overcoming the usual allylic reactivity of vinyl ethylene carbonates (VECs) via a tandem C-H/C-O bond activation sequence is disclosed herein. This methodology provides useful molecular scaffolds following two distinct pathways in highly step- atom-economical manner. The pathway features challenging beta-hydroxide elimination Rh-catalyzed transformation, we have observed unusual competing such as an oxidative insertion MeOH into Rh(III) give putative Rh(V)-H intermediate. Mechanistic insights unveil new mode open avenue for divergent catalysis. Post synthetic modification annulated products add additional advantage methodology.

Language: Английский

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Theoretical Studies on the Reaction Mechanism for the Cycloaddition of Zwitterionic π-Allenyl Palladium Species: Substrate-Controlled Isomerization

Molecules, Journal Year: 2024, Volume and Issue: 30(1), P. 103 - 103

Published: Dec. 30, 2024

Zwitterionic π-allenyl palladium species are newly developed intermediates. A substrate-controlled step existed in the cycloaddition of zwitterionic with tropsulfimides or tropones. With assistance previously experimental studies, allenyl/propargyl was provenly found by HRMS. Further DFT calculation studies show that generated through oxidative addition Pd(0), which can be promoted Lewis acid like Yb(OTf)3, and more likely undergoes an outer sphere nucleophilic attack. The isomerization is caused difference dissociation energy between intermediation tropones, forming specificity.

Language: Английский

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Palladium-catalyzed decarboxylative [2 + 3] cyclocarbonylation reactions of [60]fullerene: selective synthesis of [60]fullerene-fused 3-vinylcyclopentan-4-ones and cyclopentane-4-carbaldehydes

Organic Chemistry Frontiers, Journal Year: 2022, Volume and Issue: 9(20), P. 5564 - 5570

Published: Jan. 1, 2022

A new palladium-catalyzed decarboxylative strategy has been developed toward direct cyclocarbonylation of [60]fullerene, selectively furnishing novel [60]fullerene-fused 3-vinylcyclopentan-4-ones and cyclopentane-4-carbaldehydes.

Language: Английский

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Highly diastereo- and enantioselective synthesis of multisubstituted allylic amino acid derivatives by allylic alkylation of a chiral glycine-based nickel complex and vinylethylene carbonates

Organic & Biomolecular Chemistry, Journal Year: 2022, Volume and Issue: 20(24), P. 4894 - 4899

Published: Jan. 1, 2022

We report a palladium catalyzed allylic alkylation of chiral glycine-based nickel complex with vinylethylene carbonates under mild conditions.

Language: Английский

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