Well-Defined Low-Valent Cobalt Complexes in Catalysis: An Overview

Organometallics, Journal Year: 2024, Volume and Issue: 43(9), P. 895 - 923

Published: April 18, 2024

For decades, transition-metal catalysts based on noble metals have proven to be highly efficient for a wide range of organic transformations. However, due their low abundance and volatile price the use such is now critical economy. Thus, more sustainable alternatives mandatory abundant first-row transition are becoming interesting challengers. Among them low-valent 3d appeared as best candidates, they intrinsically reactive than high-valent ones. this reactivity implies that these complexes often generated in situ, putting further away aspect atom economy waste. To circumvent get insight mechanism reaction, concept well-defined has emerged. In area, its historic development trouble associated with preparation other complexes, cobalt appears an important player. review, after definition what complex presentation (pre)catalyst also known "single-component" strategy we will report syntheses applications catalysis classified by oxidation state ligand environment.

Language: Английский

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Cobalt-catalyzed double hydroboration of pyridines

Chemical Science, Journal Year: 2024, Volume and Issue: 15(14), P. 5201 - 5210

Published: Jan. 1, 2024

Cobalt(ii) complexes were prepared from a modular phosphinopyridonate platform and applied to the hydroboration of pyridines. The synthetically useful, yet challenging, double toward tetrahydropyridine derivatives was successfully performed with high activity regiocontrol. This new method enabled direct synthesis N-heterocyclic allylic boronates commercial pyridines pinacolborane (HBpin). One-pot acetylation afforded bench-stable borylated N-acetyl tetrahydropyridines in good yields. synthetic utility this procedure demonstrated by gram-scale hydroboration-acetylation sequence followed chemical diversification. Mechanistic experiments indicated metal-ligand cooperativity involving ligand-centered C-H activation intermediacy cobalt(iii) hydride species.

Language: Английский

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Recent strategies and developments in the hydroboration of N-Heteroarenes mediated by transition and rare-earth metal complexes

Inorganica Chimica Acta, Journal Year: 2025, Volume and Issue: unknown, P. 122594 - 122594

Published: Feb. 1, 2025

Language: Английский

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Selective Cascading Hydroboration of N-Heteroarenes via Cobalt Catalysis

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(5), P. 3582 - 3595

Published: Feb. 20, 2024

Selective cascading hydroelementation of N-heteroarenes represented by pyridines can provide diverse accesses to not only dihydro products but also tetrahydro and piperidines bearing an sp3 C–E bond (E = B, Si, etc.). Herein, we describe the Co-catalyzed hydroboration quinolines pyridines. A precatalyst Co(acac)2 with a P∧N ligand (R-Fc-PHOX; R tBu, Ph, or iPr) enabled stepwise HBpin (1 3 equiv) exclusively give 1,2-DHQ C4-borylated tetrahydroquinolines in high efficiency (TON up 2000/[Co] gram scale TOF 500/h). similar system using monodentate phosphine efficiently catalyzed regio- stereoselective double furnish range 1,3-diboryl-1,2,3,4-tetrahydropyridines, which were situ hydrogenated corresponding C–B β nitrogen atom. Experimental mechanistic studies on quinoline suggested insights as follows: (1) precursor active (P∧N)Co hydride species is (P∧N)Co(acac)2, involved catalyst initiation step induction period. (2) The first phase highly 1,2-selective. (3) C(sp3)–B formation second turnover-limiting overall catalytic process. (4) under kinetic differentiation.

Language: Английский

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Dearomative Transformation of Pyridin-3-ols into 2,3,6,7-Tetrahydro-1H-2,6-methanobenzo[d]azonin-12-ones via Oxidopyridinium/o-Quinodimethane (5 + 4) Cycloaddition

Organic Letters, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 23, 2024

We report the dearomative transformation of pyridin-3-ols via oxidopyridinium (5 + 4) cycloaddition with o-quinodimethanes, leading to 2,3,6,7-tetrahydro-1H-2,6-methanobenzo[d]azonin-12-ones. The chemoselective derivatization obtained cycloadduct was also investigated demonstrate synthetic potential cycloadduct.

Language: Английский

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Synthesis of Borylated Tetrahydroquinolines via Low-Valent Cobalt Catalysis

Synfacts, Journal Year: 2023, Volume and Issue: 20(01), P. 0044 - 0044

Published: Dec. 8, 2023

Key words cobalt catalysis - tetrahydroquinolines hydroborylation

Language: Английский

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