Chemoselective and Catalyst‐Free O‐Borylation of Silanols: A Facile Access to Borasiloxanes

Kuciński, Krzysztof; Hreczycho, Grzegorz

doi:10.1002/cssc.201701648

Cited by 34 publications

(16 citation statements)

References 41 publications

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“…Prior to our communication, a handful of catalysed processes relying on late‐transition‐metal complexes, Sc(OTf) 3 or Mo(CO) 6 had been shown to yield borasiloxanes upon coupling of silanols or hydrosilanes with hydroboranes, diboranes, boraxanes, allylborane or vinylboronates. In a reversed and complementary methodology to borinic acid‐hydrosilane dehydrocoupling, silanols and pinacol‐ and catecholborane can also be coupled in the absence of specific catalyst . The known processes for the production of borasiloxanes are summarised in Scheme .…”

Section: Introductionmentioning

confidence: 99%

Barium‐Catalysed Dehydrocoupling of Hydrosilanes and Borinic Acids: A Mechanistic Insight

Coz

Zhang

Roisnel

et al. 2020

Chemistry A European J

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Two very rare cases of barium boryloxides, the homoleptic [Ba(OB{CH(SiMe3)2}2)2⋅C7H8] and the heteroleptic [{LONO4}BaOB{CH(SiMe3)2}2] stabilised by the multidentate aminoetherphenolate {LONO4}−, are presented, and their structural properties are discussed. The electron‐deficient [Ba(OB{CH(SiMe3)2}2)2⋅C7H8] shows, in particular, resilient η6‐coordination of the toluene molecule. Together with its amido parents [Ba{N(SiMe3)2}2⋅thf2] and [Ba{N(SiMe3)2}2]2, this complex catalyses the fast and chemoselective dehydrocoupling of borinic acids R2BOH and hydrosilanes HSiR′3, yielding borasiloxanes R2BOSiR′3 in a controlled fashion. The assessment of substrate scope indicates that, for now, the reaction is limited to bulky borinic acids. Kinetic analysis shows that the rate‐limiting step of the catalytic manifold traverses a dinuclear transition state. A detailed mechanistic scenario is proposed on the basis of DFT computations, the results of which are fully consistent with experimental data. It consists of a stepwise process with rate‐determining nucleophilic attack of a metal‐bound O‐atom onto the incoming hydrosilane, involving throughout dinuclear catalytically active species.

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Section: Introductionmentioning

confidence: 99%

Barium‐Catalysed Dehydrocoupling of Hydrosilanes and Borinic Acids: A Mechanistic Insight

Coz

Zhang

Roisnel

et al. 2020

Chemistry A European J

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“…Urban land use includes industrial hubs, residences, major infrastructure such as ports, and other uses designed to support concentrated human settlement. While these activities are heterogeneous, they often spatially covary and are evaluated together under proxies like Total Impervious Area or the Landscape Development Intensity Index (Brabec et al, 2002;Brown and Vivas, 2005;Dadhich et al, 2017). Urban land use affects corals through a number of pathways, including (1) habitat loss from nearshore earthmoving, (2) industrial pollution from factories and power plants, (3) untreated sewage from both sewer outfalls and underground storage tanks, (4) stormwater runoff from impervious pavement, (5) marine debris and artificial substrates, and (6) impacts of artificial light on reef organisms like zooplankton, polychaete worms, and reef fish (Aubrecht et al, 2008;DeGeorges et al, 2010;Suchley and Alvarez-Filip, 2018).…”

Section: Urban Land Usementioning

confidence: 99%

Land Use Impacts on Coral Reef Health: A Ridge-to-Reef Perspective

2019

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Over 60% of the world's reefs experience damage from local activities such as overfishing, coastal development, and watershed pollution. Land-based sources of pollution are a critical threat to coral reefs, and understanding "ridge-to-reef" changes is urgently needed to improve management and coral survival in the Anthropocene. We review existing literature on spatial-ecological connections between land use and coral health, specifically examining vegetative, agricultural, urban, and other land-use types. In general, forested land use is positively related to metrics of coral condition, while anthropogenic land uses like urban development and agriculture drive a decline in coral cover, diversity, colony size, and structural complexity. However, land-use and land-cover impacts vary across time and space, and small portions of the landscape (e.g., discrete segments of unpaved roads, grazed and scalded hillsides) may have an outsized effect on reef pollution, presenting opportunities for targeted conservation. Some coral species show resilience under land-use and land-cover change, and the impact of land use on coral recovery from bleaching remains an active area of research. Finally, a spatial bibliography of existing literature reveals that most ridge-to-reef studies focus on a handful of regional hotspots, surface water, and watershed-scale dynamics; more research is needed to address groundwater connectivity and to compare land-use impacts across multiple regions and scales. Approaches from landscape ecology that assess spatial patterns of, and synergies between, interlocking land cover may assist conservation managers in designing more resilient reefscapes.

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“…Both of them provide the process to some extent following green chemistry aspects. Recently, our group developed some of procedures utilizing pinacolborane (HBPin) in O ‐borylation of silanols/polyhedral oligomeric silsesquioxane silanols (POSS silanols), and hydroboration of carbonyls. [5u], [6d] Our studies have shown that aldehydes can be efficiently transformed into their boronic ester derivatives under catalyst‐free and solvent‐free conditions (mostly at elevated temperature).…”

Section: Figurementioning

confidence: 99%

Potassium Fluoride‐Catalyzed Hydroboration of Aldehydes and Ketones: Facile Reduction to Primary and Secondary Alcohols

Kuciński

Hreczycho

2020

Eur J Org Chem

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A catalytic hydroboration of various ketones and aldehydes can be achieved in the presence of inexpensive and commercially available inorganic salts containing fluoride an-The hydroboration of unsaturated systems [1] (the sister's process to the hydrosilylation) [2] is becoming an issue of increasing importance to scientists. The best evidence of this is the dynamically growing number of scientific reports over recent years (more than 200 articles annually in accordance with WoS). Therefore, a wide range of different catalysts have already been applied for this purpose, starting with transition metal [3] and rare-earth element complexes, [4] through main group catalysts, [5] up to the catalyst-free approaches (Figure 1). [6] More or less significant drawbacks characterize all of them (e.g., expensive or sensitive reagents/catalysts, elevated temperature, etc.).The primary attention should be paid to synthetic solutions using main-group compounds as catalysts, as well as on catalyst-free approaches. Both of them provide the process to some extent following green chemistry aspects. Recently, our group developed some of procedures utilizing pinacolborane (HBPin) in O-borylation of silanols/polyhedral oligomeric silsesquioxane silanols (POSS silanols) [7,8] and hydroboration of carbonyls. [5u,6d] Our studies have shown that aldehydes can be efficiently transformed into their boronic ester derivatives under catalyst-free and solvent-free conditions (mostly at elevated temperature). However, ketones were inactive in this process. Last results done by Wang et al., have shown that in case of ketones, a higher temperature is necessary to improve the conversion rates.[6e] Therefore, we continued our studies to find a solution, which will be applicable to both carbonyl moieties. As a result, a very efficient LiHBEt 3 -catalyzed procedure has been discovered. [5u] Nonetheless, lithium triethylborohydride is very sensitive and requires special care due to its high reactivity. Consequently, in view of our previous reports, the aim of this work [a]

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Chemoselective and Catalyst‐Free O‐Borylation of Silanols: A Facile Access to Borasiloxanes

Cited by 34 publications

References 41 publications

Barium‐Catalysed Dehydrocoupling of Hydrosilanes and Borinic Acids: A Mechanistic Insight

Barium‐Catalysed Dehydrocoupling of Hydrosilanes and Borinic Acids: A Mechanistic Insight

Land Use Impacts on Coral Reef Health: A Ridge-to-Reef Perspective

Potassium Fluoride‐Catalyzed Hydroboration of Aldehydes and Ketones: Facile Reduction to Primary and Secondary Alcohols

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