79422-00-7Relevant academic research and scientific papers
Mechanistic insights into boron-catalysed direct amidation reactions
Arkhipenko, Sergey,Sabatini, Marco T.,Batsanov, Andrei S.,Karaluka, Valerija,Sheppard, Tom D.,Rzepa, Henry S.,Whiting, Andrew
, p. 1058 - 1072 (2018/02/07)
The generally accepted monoacyloxyboron mechanism of boron-catalysed direct amidation is brought into question in this study, and new alternatives are proposed. We have carried out a detailed investigation of boron-catalysed amidation reactions, through study of the interaction between amines/carboxylic acids and borinic acids, boronic acids and boric acid, and have isolated and characterised by NMR/X-ray crystallography many of the likely intermediates present in catalytic amidation reactions. Rapid reaction between amines and boron compounds was observed in all cases, and it is proposed that such boron-nitrogen interactions are highly likely to take place in catalytic amidation reactions. These studies also clearly show that borinic acids are not competent catalysts for amidation, as they either form unreactive amino-carboxylate complexes, or undergo protodeboronation to give boronic acids. It therefore seems that at least three free coordination sites on the boron atom are necessary for amidation catalysis to occur. However, these observations are not consistent with the currently accepted 'mechanism' for boron-mediated amidation reactions involving nucleophilic attack of an amine onto a monomeric acyloxyboron intermediate, and as a result of our observations and theoretical modelling, alternative proposed mechanisms are presented for boron-mediated amidation reactions. These are likely to proceed via the formation of a dimeric B-X-B motif (X = O, NR), which is uniquely able to provide activation of the carboxylic acid, whilst orchestrating the delivery of the amine nucleophile to the carbonyl group. Quantum mechanical calculations of catalytic cycles at the B3LYP+D3/Def2-TZVPP level (solvent = CH2Cl2) support the proposal of several closely related potential pathways for amidation, all of which are likely to be lower in energy than the currently accepted mechanism.
GLUTATHIONE-DETECTING FLUORESCENT PROBE
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Paragraph 0242, (2017/04/11)
[Problem] To provide the following: a novel fluorescent probe for detecting a compound, such as glutathione, that contains a —SH group; a detection method using said fluorescent probe; and a detection kit containing said probe. [Solution] A fluorescent pr
Oxidative coupling of aryl boron reagents with sp3-carbon nucleophiles: The enolate chan–evans–lam reaction
Moon, Patrick J.,Halperin, Heather M.,Lundgren, Rylan J.
supporting information, p. 1894 - 1898 (2016/12/03)
Reported is a versatile new oxidative method for the arylation of activated methylene species. Under mild reaction conditions (RT to 40°C), Cu(OTf)2mediates the selective coupling of functionalized aryl boron species with a variety of stabilized sp3-nucleophiles. Tertiary malonates and amido esters can be employed as substrates to generate quaternary centers. Complementing either traditional cross-coupling or SNAr protocols, the transformation is chemoselective in the presence of halogen electrophiles, including aryl bromides and iodides. Substrates bearing amide, sulfonyl, and phosphonyl groups, which are not amenable to coupling under mild Hurtley-type conditions, are suitable reaction partners.
Chiral tetrafluorobenzobarrelenes as effective ligands for rhodium-catalyzed asymmetric 1,4-addition of arylboroxines to β,β-disubstituted α,β-unsaturated ketones
Shintani, Ryo,Takeda, Momotaro,Nishimura, Takahiro,Hayashi, Tamio
supporting information; experimental part, p. 3969 - 3971 (2010/09/03)
(Chemical Equotion Present) Lock, Stock and Two Smoking Barrelenes: The rhodium-catalyzed 1,4-addition of readily available arylboronic acid anhydrides to simple β,β-disubstituted α,βunsaturated ketones creates quaternary carbon stereocenters with high enantiomeric excesses using a chiral tetrafluorobenzobarrelene ligand.
