Controllable Isomerization of Alkenes by Dual Visible‐Light‐Cobalt Catalysis

Meng, Qing‐Yuan; Schirmer, Tobias E.; Katou, Kousuke; Koenig, Burkhard

doi:10.1002/ange.201900849

Cited by 39 publications

(14 citation statements)

References 62 publications

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“…In recent years, cobalt compounds have been extensively studied as catalysts for hydroboration and isomerization of alkenes [55][56][57][58][59][60][61][62][63] . In 2015, Chirik and coworkers showed one example of cobalt-catalyzed hydroboration of a boryl-containing terminal alkene to give a gem-bis(boryl)alkane product by taking the advantage of boryl-directed alkene isomerization 59 .…”

mentioning

confidence: 99%

Versatile cobalt-catalyzed regioselective chain-walking double hydroboration of 1,n-dienes to access gem-bis(boryl)alkanes

2020

Nat Commun

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Double hydroboration of dienes is the addition of a hydrogen and a boryl group to the two double bonds of a diene molecule and represents a straightforward and effective protocol to prepare synthetically versatile bis(boryl)alkanes, provided that this reaction occurs selectively. However, this reaction can potentially yield several isomeric organoboron products, and it still remains a challenge to control the regioselectivity of this reaction, which allows the selective production of a single organoboron product, in particular, for a broad scope of dienes. By employing a readily available cobalt catalyst, here we show that this double hydroboration yields synthetically useful gem-bis(boryl)alkanes with excellent regioselectivity. In addition, the scope of dienes for this reaction is broad and encompasses a wide range of conjugated and non-conjugated dienes. Furthermore, mechanistic studies indicate that this cobalt-catalyzed double hydroboration occurs through boryl-directed chain-walking hydroboration of alkenylboronates generated from anti-Markovnikov 1,2-hydroboration of 1,n-diene.

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mentioning

confidence: 99%

Versatile cobalt-catalyzed regioselective chain-walking double hydroboration of 1,n-dienes to access gem-bis(boryl)alkanes

2020

Nat Commun

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“…No conversion was observed in the dark without pinacolborane. Although alkene isomerisation has been reported with a wide array of metal catalysts including non-noble metal examples with nickel 37 or cobalt [38][39][40][41][42][43][44][45] , we believed that this method compares well, requiring no additional co-catalysts, ligands or bases. 46 It is noteworthy that few existing alkene isomerisation methods are reported to isomerise this particular electron-deficient substrate.…”

Section: Resultsmentioning

confidence: 99%

Dual-Function, Light Switchable Cobalt Catalysis via Active Site Metamorphosis

Bergamaschi¹,

Beltran²,

Teskey³

2019

Preprint

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Switchable catalysis offers opportunities to control the rate or selectivity of a reaction via a stimulus such as pH or light. However, few examples of switchable catalytic systems that can facilitate multiple processes exist. Here we report a rare example of such dual-functional, switchable catalysis. Featuring an easily prepared, bench-stable cobalt(I) hydride complex in conjunction with pinacolborane, we can completely alter the reaction outcome between two widely employed transformations – olefin migration and hydroboration – with visible light as the sole trigger. This dichotomy arises from ligand photodissociation which leads to metamorphosis of the active catalytic site, resulting in divergent mechanistic pathways.

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“…On the other hand, Co−H mediated hydrocarbonation of alkenes represents another important reaction pattern in photoredox/cobalt dual catalysis (Scheme 1Aa). In this respect, Rovis, [5] Maji, [6] König, [7] Collins [8] and other groups [9] have made excellent contributions. However, after extensive literatures survey, it is surprising to discover that the photochemically generated low‐valent cobalt complexes were rarely utilized in synthetic chemistry (Scheme 1Ab) [10] .…”

Section: Methodsmentioning

confidence: 99%

Hydroxyl Assisted, Photoredox/Cobalt Co‐catalyzed Semi‐Hydrogenation and Tandem Cyclization of o‐Alkynylphenols for Access to 2,3‐Dihydrobenzofurans

Tian

Zhu

et al. 2020

Adv Synth Catal

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Herein, a hydroxyl assisted, photoredox/cobalt co‐catalyzed semi‐hydrogenation and tandem cyclization of o‐alkynylphenols is developed towards direct assembly of 2,3‐dihydrobenzofurans. Moderate to good yields were obtained for a range of sterically and electronically diverse 2‐propynolphenols under mild conditions. Mechanistic studies demonstrated the inevitable role of the alcoholic hydroxyl group with (Z)‐alkene as the real intermediate. Finally, a key low‐valent cobalt catalyzed intramolecular hydroetherification of alkene is proposed.magnified image

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Controllable Isomerization of Alkenes by Dual Visible‐Light‐Cobalt Catalysis

Abstract: Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.org/10.

Cited by 39 publications

References 62 publications

Versatile cobalt-catalyzed regioselective chain-walking double hydroboration of 1,n-dienes to access gem-bis(boryl)alkanes

Versatile cobalt-catalyzed regioselective chain-walking double hydroboration of 1,n-dienes to access gem-bis(boryl)alkanes

Dual-Function, Light Switchable Cobalt Catalysis via Active Site Metamorphosis

Hydroxyl Assisted, Photoredox/Cobalt Co‐catalyzed Semi‐Hydrogenation and Tandem Cyclization of o‐Alkynylphenols for Access to 2,3‐Dihydrobenzofurans

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