The Product of Catalysed Diboration of Bis(4-methoxyphenyl)ethyne by Bis(pinacolato-O,O')diboron

Clegg, William; Scott, A. J.; Lesley, Gerry; Marder, T. B.; Norman, N. C.

doi:10.1107/s0108270196003836

Cited by 8 publications

(9 citation statements)

References 3 publications

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“…It is interesting to note here that both B 2 cat 2 and B 2 pin 2 were used as diboron reagents in Pt-catalyzed diborations of alkenes, alkynes, dienes, and α,β-unsaturated carbonyl compounds. , We expect that these reactions proceed via a mechanism involving oxidative addition of the diboron reagents to the Pt(0) metal center. No metathesis is involved, and the reactivity difference of B 2 cat 2 and B 2 pin 2 is relatively small.…”

Section: Discussionmentioning

confidence: 97%

“…Transition metal boryl complexes play important roles in catalyzed boration processes such as hydroboration, diboration, dehydrogenative borylation, and other B−X addition reactions to unsaturated organics – as well as the catalyzed borylation of C−H bonds in alkanes and arenes. , In these metal boryl complexes, Bcat and Bpin are among the most popular boryl ligands as a result of their applicability to catalytic processes and the commercial availability of HBcat, HBpin, B 2 cat 2 , and B 2 pin 2 (cat = catecholato = 1,2-O 2 C 6 H 4 ; pin = pinacolato = OCMe 2 CMe 2 ). Although the boron centers in both of the boryl ligands bear vicinal diol substituents, Bcat and Bpin display different bonding characteristics and reactivities.…”

Section: Introductionmentioning

confidence: 99%

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Understanding the Higher Reactivity of B₂cat₂versus B₂pin₂in Copper(I)-Catalyzed Alkene Diboration Reactions

et al. 2008

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DFT calculations have been carried out to study the reactivity difference of B 2 cat 2 and B 2 pin 2 in the diboration reaction of alkenes catalyzed by carbene-ligated copper(I) complexes. The higher reactivity of B 2 cat 2 versus B 2 pin 2 in this reaction results largely from the enhanced electrophilicity/Lewis acidity of the former, which significantly lowers the barrier in the product-forming transmetalation step. Transmetalation reactions of B 2 cat 2 and B 2 pin 2 with (NHC)Cu-OMe have also been investigated, and the relative barriers are much closer than with analogous Cu-R systems.

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Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Understanding the Higher Reactivity of B₂cat₂versus B₂pin₂in Copper(I)-Catalyzed Alkene Diboration Reactions

et al. 2008

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“…Experimental evidence has been found for each step of the catalytic cycle. , Marder and Norman reported the crystal structures of the organic products from the diboration of alkynes with either B 2 pin 2 or B 2 cat 2 . The groups of Marder and Smith , reported the isolation and characterization of [Pt(PR 3 ) 2 (B(OR) 2 ) 2 ] complexes, which proved to be catalytically competent in the diboration of alkynes.…”

Section: 2- and 14-diborationsmentioning

confidence: 99%

Diboron(4) Compounds: From Structural Curiosity to Synthetic Workhorse

et al. 2016

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“…By far the most stable derivatives are those in which good π-donor groups are present such as amido (NR 2 ) or alkoxy (OR), the prototypical examples being B 2 (NMe 2 ) 4 ( 1 ) and B 2 (OMe) 4 ( 2 ); the former compound 1 is the primary starting material for much of diborane(4) chemistry due to its thermal stability and the availability of high yield syntheses. More recently, as part of an interest in the oxidative addition chemistry 8,9 of the B−B bond and metal-catalyzed diborations 10 of alkenes 11 and alkynes, we have characterized a series of stable, crystalline bis-catecholate 8a and bis-dithiocatecholate derivatives, and herein we describe full details of their syntheses, spectroscopic properties and aspects of bonding derived from photoelectron spectroscopic measurements and extended Hückel molecular orbital (EHMO) calculations. Also described is the tetraalkoxy compound B 2 (OCH 2 CMe 2 CH 2 O) 2 .…”

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confidence: 99%

Bis-Catecholate, Bis-Dithiocatecholate, and Tetraalkoxy Diborane(4) Compounds: Aspects of Synthesis and Electronic Structure

Lawlor¹,

Norman²,

Pickett³

et al. 1998

Inorg. Chem.

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The synthesis and characterization of a series of bis-catecholate diborane(4) compounds, B2(1,2-O2C6H4)2 (3), B2(1,2-O2-3-MeC6H3)2 (6), B2(1,2-O2-4-MeC6H3)2 (7), B2(1,2-O2-4-ButC6H3)2 (8), B2(1,2-O2-3,5-But 2C6H2)2 (9), B2(1,2-O2-3-MeOC6H3)2 (10), bis-dithiocatecholate diborane(4) compounds, B2(1,2-S2C6H4)2 (13), B2(1,2-S2-4-MeC6H3)2 (14), and tetraalkoxy diborane(4) compounds, B2(OCH2CMe2CH2O)2 (11) and B2(OCMe2CMe2O)2 (12) from B2(NMe2)4 (1) is described, as are the bis(NHMe2) adducts of 3 and 9, namely [B2(1,2-O2C6H4)2(NHMe2)2] (4) and [B2(1,2-O2-3,5-But 2C6H2)2(NHMe2)2] (5). The latter two compounds are intermediates in the formation of 3 and 9 from 1. Compound 1 is synthesized by reductive coupling of BCl(NMe2)2, which in turn is prepared from reaction of BCl3 with B(NMe2)3 in a 1:2 stoichiometry. We have also characterized [B2Cl4(NHMe2)2] (15) formed from addition of HCl to 1 prior to complete reaction with diols, and the salt, [NH2Me2][B(1,2-O2C6H4)2] (16), which arises from addition of catechol to B(NMe2)3. Thus, any B(NMe2)3 impurity present after the preparation of 1 needs to be removed by distillation prior to reaction with alcohols. The dimer, [BCl2(μ-NMe2)]2 (17) has also been characterized. This is formed from reaction of BCl3 with B(NMe2)3 if a 2:1 rather than 1:2 stoichiometry is used. Photoelectron spectra of 1, 3, 8, 11, and 12 are reported along with those of the corresponding diols, catechol, 4-But-catechol, 2,2-dimethyl-1,3-propanediol, and pinacol. The ionization energies of the B2(OR)4 compounds follow the series 8 < 3 < 12 < 11. Replacement of O for N in the B2N4 framework increases the IE by ca. 1.65 eV, whereas the presence of an aromatic ring rather than an aliphatic chain decreases the IE by ca. 1.50 eV. The presence of electron donating But-groups also decreases the IE.

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The Product of Catalysed Diboration of Bis(4-methoxyphenyl)ethyne by Bis(pinacolato-O,O')diboron

Cited by 8 publications

References 3 publications

Understanding the Higher Reactivity of B₂cat₂versus B₂pin₂in Copper(I)-Catalyzed Alkene Diboration Reactions

Understanding the Higher Reactivity of B₂cat₂versus B₂pin₂in Copper(I)-Catalyzed Alkene Diboration Reactions

Diboron(4) Compounds: From Structural Curiosity to Synthetic Workhorse

Bis-Catecholate, Bis-Dithiocatecholate, and Tetraalkoxy Diborane(4) Compounds: Aspects of Synthesis and Electronic Structure

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The Product of Catalysed Diboration of Bis(4-methoxyphenyl)ethyne by Bis(pinacolato-O,O')diboron

Cited by 8 publications

References 3 publications

Understanding the Higher Reactivity of B2cat2versus B2pin2in Copper(I)-Catalyzed Alkene Diboration Reactions

Understanding the Higher Reactivity of B2cat2versus B2pin2in Copper(I)-Catalyzed Alkene Diboration Reactions

Diboron(4) Compounds: From Structural Curiosity to Synthetic Workhorse

Bis-Catecholate, Bis-Dithiocatecholate, and Tetraalkoxy Diborane(4) Compounds: Aspects of Synthesis and Electronic Structure

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Understanding the Higher Reactivity of B₂cat₂versus B₂pin₂in Copper(I)-Catalyzed Alkene Diboration Reactions

Understanding the Higher Reactivity of B₂cat₂versus B₂pin₂in Copper(I)-Catalyzed Alkene Diboration Reactions