A borylcopper species generated from bis(pinacolato)diboron and its additions to α,β-unsaturated carbonyl compounds and terminal alkynes

Takahashi, Kou; Ishiyama, Tatsuo; Miyaura, Norio

doi:10.1016/s0022-328x(00)00826-3

Cited by 321 publications

(141 citation statements)

References 46 publications

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“…At the same time, Miyaura and co-workers reported a similar copperpromoted addition of bis(pinacolato)diboron to α,β-unsaturated ketones, esters, and nitriles using a stoichiometric amount of CuCl/LiCl and KOAc [3]. A catalytic version of this reaction soon followed from the same group, but this catalytic reaction was possible only for α,β-unsaturated ketones, similar to Hosomi's report [9]. Miyaura et al also proposed a copper-boryl species as an active nucleophilic boron source in the β-borylation reaction.…”

Section: Cu-catalyzed β-Borylationsupporting

confidence: 57%

Asymmetric Catalytic Borylation of α,β-Unsaturated Acceptors

Lee

Yun

2015

Synthesis and Application of Organoboron Compounds

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Section: Cu-catalyzed β-Borylationsupporting

confidence: 57%

Asymmetric Catalytic Borylation of α,β-Unsaturated Acceptors

Lee

Yun

2015

Synthesis and Application of Organoboron Compounds

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“…These compounds have already been synthesized. [14,15] Compared with boranes, the use of boronic acids and boronates as reagents, particularly compound 2, is advantageous due to the simplicity of the manipulation and the convenient reaction protocol employing these compounds. Bis(pinacolato)diboron is considerably more stable towards oxygen and moisture than other borane analogues that cannot be handled in air due to oxidative and hydrolytic reactions of the B À H bonds.…”

Section: Introductionmentioning

confidence: 99%

Stereoselective Single (Copper) or Double (Platinum) Boronation of Alkynes Catalyzed by Magnesia‐Supported Copper Oxide or Platinum Nanoparticles

Grirrane

Corma

Garcı́a

2011

Chemistry A European J

107

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Copper(II) oxide nanoparticles supported on magnesia have been prepared from Cu(II) supported on magnesia by hydrogen reduction at 400 °C followed by storage under ambient conditions. X-ray photoelectron spectroscopy of the material clearly shows that immediately after the reduction copper(0)-metal nanoparticles are present on the magnesia support, but they undergo fast oxidation to copper oxide upon contact with the ambient for a short time. TEM images show that the catalytically active CuO/MgO material is formed of well-dispersed copper oxide nanoparticles supported on fibrous MgO. CuO/MgO exhibits a remarkable catalytic activity for the monoborylation of aromatic, aliphatic, terminal, and internal alkynes, the products being formed with high regio- (borylation at the less substituted carbon) and stereoselectivity (trans-configured). CuO/MgO exhibits complete chemoselectivity towards the monoborylation of alkynes in the presence of alkenes. Other metal nanoparticles such as gold or palladium are inactive towards borylation, but undergo undesirable oligomerization or partial hydrogenation of the C≡C triple bond. In contrast, platinum, either supported on magnesia or on nanoparticulate ceria, efficiently promotes the stereoselective diborylation of alkynes to yield a cis-configured diboronate alkene. By using platinum as the catalyst we have developed a tandem diborylation/hydrogenation reaction that gives vic-diboronated alkanes from alkynes in one pot.

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“…The catalytic cycle commences with the insertion of the in situ-generated Cu À B bond into a C=C bond, which is activated by the coordination of a base to boron. [9] Although the intermediate formed is in equilibrium between O-enolate and C-enolate tautomers, Yun et al revealed there is a preference for C-enolate over Oenolate.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Boron Conjugate Additions to Enones in Water Catalyzed by Copper(0)

Kitanosono

Kobayashi

2013

Asian J Org Chem

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Dedicated to Professor Teruaki Mukaiyama on the occasion of the 40th anniversary of the Mukaiyama aldol reaction.Abstract: The use of copper(0) powder in water enables chiral induction as well as high catalytic activity. Water plays a prominent role to determine both the catalytic activity and enantioselection. Elevated temperature is indispensable for the regular reaction pathway, and an active species tends to aggregate after the completion of the reaction. Selective deuteration implies enantiofacial differentiation of the deuteron toward an O-enolate intermediate. Strict substrate specificity suggests the vital interaction between copper (0) and an enone. A very weak isotope effect is indicative of instantaneous protonation. Accordingly, a redox copper cycle (0!II) is tentatively proposed, in which transmetalation of a cyclometalated enone with diboron would furnish a boron enolate, followed by hydrolysis and reductive elimination. However, a single electron transfer process cannot be excluded on the available evidence and a more detailed mechanistic study is under way.

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A borylcopper species generated from bis(pinacolato)diboron and its additions to α,β-unsaturated carbonyl compounds and terminal alkynes

Cited by 321 publications

References 46 publications

Asymmetric Catalytic Borylation of α,β-Unsaturated Acceptors

Asymmetric Catalytic Borylation of α,β-Unsaturated Acceptors

Stereoselective Single (Copper) or Double (Platinum) Boronation of Alkynes Catalyzed by Magnesia‐Supported Copper Oxide or Platinum Nanoparticles

Asymmetric Boron Conjugate Additions to Enones in Water Catalyzed by Copper(0)

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