Reactivity scales for quantifying polar organic reactivity: the benzhydrylium methodology

Mayr, Herbert

doi:10.1016/j.tet.2015.05.055

Cited by 121 publications

(120 citation statements)

References 70 publications

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“…This is challenging in view of the triflate ion’s nucleofugal properties, and suggests that nucleophilic reactions of triflate may be more common than is generally believed. Triflate is not on any published scale of nucleophilicity including Mayr’s scale, 11–12 which also does not contain mesylate, or iodide. Nevertheless, rate constants for the reaction of mesylate with 1-arylvinyl cations in acetonitrile were found to be ~10 2 -fold less than those of acetate or iodide and some fifteen and seventy five-fold greater than those of bromide or chloride, respectively, 13 suggesting that sulfonates may be more nucleophilic than commonly perceived.…”

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confidence: 99%

Trifluoromethanesulfonate Anion as Nucleophile in Organic Chemistry

2017

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Although the triflate ion is not generally perceived as a nucleophile many examples of its behavior as such exist in the literature. This synopsis presents an overview of such reactions, in which triflate may be either a stoichiometric or catalytic nucleophile, leading to the suggestion that nucleophilic catalysis by triflate may be more common than generally accepted, albeit hidden by the typical reactivity of organic triflates which complicates their observation as intermediates.

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confidence: 99%

Trifluoromethanesulfonate Anion as Nucleophile in Organic Chemistry

2017

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“… 1–6 In particular, in the case of diarylmethyl (Ar 2 CH) compounds, the in situ generated carbocations are used to study their reactions with nucleophiles 6,7 . Ph 2 CH + and its various derivatives serve as reference electrophiles for one of the most extensive reactivity scales covering 40 orders of magnitude which is being developed by Mayr and coworkers 7–10 . Different leaving groups (LGs) are used depending on the conditions under which the reactive species are generated 4–6 .…”

Section: Introductionmentioning

confidence: 99%

Molecular features in complex environment: Cooperative team players during excited state bond cleavage

Thallmair

Roos

Vivie‐Riedle

2016

Structural Dynamics

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Photoinduced bond cleavage is often employed for the generation of highly reactive carbocations in solution and to study their reactivity. Diphenylmethyl derivatives are prominent precursors in polar and moderately polar solvents like acetonitrile or dichloromethane. Depending on the leaving group, the photoinduced bond cleavage occurs on a femtosecond to picosecond time scale and typically leads to two distinguishable products, the desired diphenylmethyl cations (Ph2CH+) and as competing by-product the diphenylmethyl radicals (Ph2CH•). Conical intersections are the chief suspects for such ultrafast branching processes. We show for two typical examples, the neutral diphenylmethylchloride (Ph2CH–Cl) and the charged diphenylmethyltriphenylphosphonium ions (Ph2CH−PPh3+) that the role of the conical intersections depends not only on the molecular features but also on the interplay with the environment. It turns out to differ significantly for both precursors. Our analysis is based on quantum chemical and quantum dynamical calculations. For comparison, we use ultrafast transient absorption measurements. In case of Ph2CH–Cl, we can directly connect the observed signals to two early three-state and two-state conical intersections, both close to the Franck-Condon region. In case of the Ph2CH−PPh3+, dynamic solvent effects are needed to activate a two-state conical intersection at larger distances along the reaction coordinate.

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“…[11] We envisioned that SKP/Pd-catalyzed AAA of MBH adducts with nucleophiles of b-ketocarbonyl compounds [12] might provide an excellent approach for the construction of vicinal chiral tertiary and quaternary centers.Accordingly,the reaction of the MBH adduct 1a and b-ketoester 2a was taken for aproof-of-concept prototype to survey the reaction conditions (Table 1). [11] We envisioned that SKP/Pd-catalyzed AAA of MBH adducts with nucleophiles of b-ketocarbonyl compounds [12] might provide an excellent approach for the construction of vicinal chiral tertiary and quaternary centers.Accordingly,the reaction of the MBH adduct 1a and b-ketoester 2a was taken for aproof-of-concept prototype to survey the reaction conditions (Table 1).…”

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Palladium‐Catalyzed Asymmetric Construction of Vicinal Tertiary and All‐Carbon Quaternary Stereocenters by Allylation of β‐Ketocarbonyls with Morita–Baylis–Hillman Adducts

et al. 2017

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Palladium-catalyzed regio-, diastereo-, and enantioselective allylic alkylation of β-ketocarbonyls with Morita-Baylis-Hillman adducts has been developed using a spiroketal-based diphosphine (SKP) as the ligand, thus affording a range of densely functionalized products bearing vicinal tertiary and all-carbon quaternary stereodyad in high selectivities. The utility of the protocol was demonstrated by the facile synthesis of some complex molecules by simple product transformations.

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Reactivity scales for quantifying polar organic reactivity: the benzhydrylium methodology

Cited by 121 publications

References 70 publications

Trifluoromethanesulfonate Anion as Nucleophile in Organic Chemistry

Trifluoromethanesulfonate Anion as Nucleophile in Organic Chemistry

Molecular features in complex environment: Cooperative team players during excited state bond cleavage

Palladium‐Catalyzed Asymmetric Construction of Vicinal Tertiary and All‐Carbon Quaternary Stereocenters by Allylation of β‐Ketocarbonyls with Morita–Baylis–Hillman Adducts

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