Activation of Dinitrogen as A Dipolarophile in 1,3-Dipolar Cycloadditions: A Theoretical Study Using Nitrile Imines as “Octet” 1,3-Dipoles

Montero‐Campillo, M. Merced; Alkorta, Ibón; Elguero, José

doi:10.1038/s41598-017-05708-z

Cited by 10 publications

(8 citation statements)

References 28 publications

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“…The beryllium bond is one of the strongest NCIs between neutral molecules. It produces important changes in the properties of the molecules involved in the interaction, such as a significant increment of the acidity of the interacting systems, , a change in the nature of the halogen bond in ternary complexes, a spontaneous production of radicals, as well as having the possibility to act as a catalyst . In addition, the importance and biological implications of the π-hole in beryllium bonds have been explored in the literature …”

Section: Introductionmentioning

confidence: 99%

Mutual Influence of Pnicogen Bonds and Beryllium Bonds: Energies and Structures in the Spotlight

et al. 2020

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Pnicogen bonds, which are weak noncovalent interactions (NCIs), can be significantly modified by the presence of beryllium bonds, one of the strongest NCIs known. We demonstrate the importance of this influence by studying ternary complexes in which both NCIs are present, that is, the ternary complexes formed by a nitrogen base (NH 3 , NHCH 2 , and NCH), a phosphine (fluorophosphane, PH 2 F) and a beryllium derivative (BeH 2 , BeF 2 , BeCl 2 , BeCO 3 , and BeSO 4 ). Energies, structures, and nature of the chemical bonding in these complexes are studied by means of ab initio computational methods. The pnicogen bond between the nitrogen base and the phosphine and the beryllium bond between the fluorine atom of fluorophosphane and the beryllium derivative show large cooperativity effects both on energies and geometries, with dissociation energies up to 296 kJ mol −1 and cooperativity up to 104 kJ mol −1 in the most strongly bound complex, CH 2 HN:PH 2 F:BeSO 4 . In the complexes between the strongest nitrogen bases and the strongest beryllium donors, phosphorus-shared and phosphorus-transfer bonds are found.

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Section: Introductionmentioning

confidence: 99%

Mutual Influence of Pnicogen Bonds and Beryllium Bonds: Energies and Structures in the Spotlight

et al. 2020

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“…Because it is a through space-effect, CFGs can also be incorporated into an external catalyst, analogous to our work with Diels−Alder reactions. 31 Alternatively metal complexation is another potential strategy to harness these electrostatic effects, and in this respect, we note that Lewis acid complexation has been used to increase the rate of the reverse reaction, 34 and the associated transition-state stabilization would also increase the forward reaction. Finally, we note that combinations of CFGs and other barrier-lowering strategies could yield further improvements in rate.…”

Section: ■ Introductionmentioning

confidence: 99%

Electrostatic Activation of Tetrazoles

2020

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Photoactivation of tetrazoles to form nitrile imines primed for 1,3-dipolar cycloaddition reactions is of widespread utility in chemistry. In contrast, the corresponding thermal reactions usually possess prohibitively high barriers and have garnered significantly less attention. Here, computational chemistry at the M06-2X/6-31+G(d,p) level of theory with SMD solvent corrections is used to show that these thermal activation barriers can be significantly reduced through the use of nonconjugated charged functional groups (CFGs). For 2,5-dimethyl-tetrazole, a positive CFG on the N-methyl (2-position) lowers the fragmentation barrier by around 80 kJ mol–1 in the gas phase, while a negative charge has a smaller opposite effect. These CFG effects remain significant even in polar solvents, with barrier lowering on the order of 30 kJ mol–1 in dimethyl sulfoxide and acetonitrile. In practical terms, the positive CFG decreases the fragmentation half-life of 2,5-dimethyl-tetrazole in refluxing o-xylene from 300,000 years to 1 week. While the resulting nitrile imine is stabilized, its subsequent 1,3-cycloaddition with N-methylmaleimide remains highly facile. Electrostatic effects on a range of 2-phenyl-5-methyltetrazoles, 2-methyl-5-phenyl-tetrazoles, and 2,5-diphenyl-tetrazoles follow similar trends and are explicable largely in terms of the stabilization of the developing dipole in the transition state.

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“…[ 191 ] Given the broad applicability and practicality of this tactic, there is no doubt that these reactions will find wide implications in tetrazole chemistry, meanwhile in‐depth mechanistic study and divergent regio‐control are also suggested to be put on the agenda. [ 192,193 ]…”

Section: Cyclization and Cycloaddition Reactions For The Constructionmentioning

confidence: 99%

Aryl DiazoniumSalt‐TriggeredCyclization and Cycloaddition Reactions: Past, Present, and Future

et al. 2020

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Aryl diazonium salts occupy a privileged role in synthetic chemistry owing to their ready availability and versatile reactivity. While their applications in accessing diversely functionalized arene derivatives via denitrogenation‐coupling and reduction/addition reactions have been well recognized by practitioners in both academia and industry, recent renaissance in chemical transformations of retaining the key N2‐unit has emerged as a powerful technique to construct various N‐heterocycles. This review covers the history and latest advances in cyclization and cycloaddition reactions using aryl diazonium salts as N2‐annulation synthons. The scope, applications, and opportunities in exploring new chemical space by this sustainable strategy are summarized and discussed.

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Activation of Dinitrogen as A Dipolarophile in 1,3-Dipolar Cycloadditions: A Theoretical Study Using Nitrile Imines as “Octet” 1,3-Dipoles

Cited by 10 publications

References 28 publications

Mutual Influence of Pnicogen Bonds and Beryllium Bonds: Energies and Structures in the Spotlight

Mutual Influence of Pnicogen Bonds and Beryllium Bonds: Energies and Structures in the Spotlight

Electrostatic Activation of Tetrazoles

Aryl DiazoniumSalt‐TriggeredCyclization and Cycloaddition Reactions: Past, Present, and Future

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