Hydrogen‐bond basicity of nitriles

Berthelot, M.; Helbert, Maryvonne; Laurence, Christian; Questel, Jean‐Yves Le

doi:10.1002/poc.610060508

Cited by 41 publications

(33 citation statements)

References 21 publications

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“…A careful structural analysis of both donor and acceptors lead us to include route B, in which the active donor species was oxocarbenium ion II. The incipient acceptor could form hydrogen bonding 39,40 with the nitrile 41 functional group III). Preceding any direct glycosylation, the acceptor would be driven to target the anomeric carbocation from an axial trajectory to generate the 1,2-cis product.…”

Section: Discussionmentioning

confidence: 99%

The intriguing dual-directing effect of 2-cyanobenzyl ether for a highly stereospecific glycosylation reaction

Hoang

Liu

2014

Nat Commun

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The diverse presence as well as their very specific bio-responses of glycoconjugates found in all living species requires scientists to synthesize the precise structure of these complex oligosaccharides for various studies on glycoscience. Very few approaches were able to offer the sole a-or b-glycosylated products, even at the cost of complicating the preparative route or usage of exotic chiral auxiliaries to drive the stereoselectivity. In this report, the unification of solvent assistance and neighbouring group participation concepts have led us to the use of 2-cyanobenzyl ether as the dual-directing auxiliary for stereospecific construction of a-and b-glycosidic bonds from a single starting material, and both isomers can be obtained in exclusive stereoselectivity. This work demonstrates the difference in reactivities of glycosyl acceptors can be employed to completely drive the stereoselectivity, drawing the parallel comparison with the arming/disarming concept, which has been exclusively confined to glycosyl donors.

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Section: Discussionmentioning

confidence: 99%

The intriguing dual-directing effect of 2-cyanobenzyl ether for a highly stereospecific glycosylation reaction

Hoang

Liu

2014

Nat Commun

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“…To calculate a secondary value for cyanamide (83), we have used the regression line from Equation (11), which is an updated version of the equation found between the pK HB values of 19 substituted nitriles X À CN and the resonance, field and polarisability constants of the substituents X. [58] The substituent parameters used for the amino group (NH 2 ) are s þ r = À0.52, s F = 0.14 and s a = À0. 16.…”

Section: Piperidine Conformermentioning

confidence: 99%

“…[84] [e] Calculated by substituent parameters with the updated Equation (11). [58] [f] Calculated from the association constants measured in dichloromethane with pFP.…”

Section: Piperidine Conformermentioning

confidence: 99%

A Theoretical Evaluation of the pK_HBand Δ$H{{{\,\ominus}\hfill \atop {\rm HB}\hfill}}}$ Hydrogen‐Bond Scales of Nitrogen Bases

Besseau

Graton

Berthelot

2008

Chemistry A European J

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The experimental pKHB hydrogen-bond (HB) basicity scale and the corresponding DeltaH[symbol: see text]HB enthalpic scale of nitrogen compounds are extended and analysed in light of simple theoretical descriptors using the B3LYP density functional method and a medium-size basis set (6-31+G(d,p)).The selected training set includes 59 monofunctional unhindered nitrogen bases for which homogeneous and accurate experimental pKHB and DeltaH[symbol: see text]HB data have been determined by means of the association equilibrium of the bases with a reference hydrogen-bond acid, 4-fluorophenol, in CCl4. The three hybridisation states encountered in the nitrogen atom, sp, sp2 and sp3, are equally represented in this data set. A proper estimation of their experimental enthalpy (DeltaH[symbol: see text]HB) is directly attainable from the theoretical enthalpy of the complexation reaction with hydrogen fluoride (DeltaH[symbol: see text](HF)). However, a second parameter is required to calculate with good accuracy the experimental free energy of association represented by pKHB. About 99% of the variance of the pKHB scale is described by a bilinear equation using the minimum electrostatic potential (Vs,min) of the monomer in addition to the interaction energy (D0(HF). The equations are tested for an external set of 99 additional compounds including very different nitrogen bases such as ortho-substituted pyridines, polyazines and azoles.Theoretical calculations give a reliable estimation of hydrogen-bond basicity provided that the populations of the different isomers of the bases are taken into account by using the Boltzmann law, and that a specific halogen-bond interaction with the solvent CCl4 is considered for polybasic molecules.The pKHB scale can thus be extended to important classes of species experimentally inaccessible in CCl4, to polynitrogen compounds and to molecules of biological significance.

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“…Berthelot and Laurence have developed an experimentally accessible means of quantitating hydrogen-bond-accepting tendencies through the measurement of the IR frequency shift of the methanol 0-H peak when the hydrogen is complexed with a hydrogen-bond-accepting molecule (40)(41)(42)(43)(44)(45)(46). This O-H frequency shift is designated AVOH.…”

Section: Methanol Infrared 0-h Frequency Shiftmentioning

confidence: 99%

Family-independent relationships between computed molecular surface quantities and solute hydrogen bond acidity/basicity and solute-induced methanol O–H infrared frequency shifts

Hagelin¹,

Murray²,

Politzer³

et al. 1995

Can. J. Chem.

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165

140

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Family-independent relationships between computed molecular surface properties and solute hydrogen bond aciditylbasicity and solute-induced methanol 0-H infrared frequency shifts are presented. The molecular surface quantities, computed at the ab initio HFl6-31G* level, are primarily related to the electrostatic potential of the molecule, but also include the average local ionization energy on its surface.

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Hydrogen‐bond basicity of nitriles

Cited by 41 publications

References 21 publications

The intriguing dual-directing effect of 2-cyanobenzyl ether for a highly stereospecific glycosylation reaction

The intriguing dual-directing effect of 2-cyanobenzyl ether for a highly stereospecific glycosylation reaction

A Theoretical Evaluation of the pK_HBand Δ$H{{{\,\ominus}\hfill \atop {\rm HB}\hfill}}}$ Hydrogen‐Bond Scales of Nitrogen Bases

Family-independent relationships between computed molecular surface quantities and solute hydrogen bond acidity/basicity and solute-induced methanol O–H infrared frequency shifts

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Hydrogen‐bond basicity of nitriles

Cited by 41 publications

References 21 publications

The intriguing dual-directing effect of 2-cyanobenzyl ether for a highly stereospecific glycosylation reaction

The intriguing dual-directing effect of 2-cyanobenzyl ether for a highly stereospecific glycosylation reaction

A Theoretical Evaluation of the pKHBand Δ$H{{{\,\ominus}\hfill \atop {\rm HB}\hfill}}}$ Hydrogen‐Bond Scales of Nitrogen Bases

Family-independent relationships between computed molecular surface quantities and solute hydrogen bond acidity/basicity and solute-induced methanol O–H infrared frequency shifts

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A Theoretical Evaluation of the pK_HBand Δ$H{{{\,\ominus}\hfill \atop {\rm HB}\hfill}}}$ Hydrogen‐Bond Scales of Nitrogen Bases