Tris(pentafluorophenyl)borane‐Catalyzed Carbenium Ion Generation and Autocatalytic Pyrazole Synthesis—A Computational and Experimental Study

Dasgupta, Ayan; Babaahmadi, Rasool; Pahar, Sanjukta; Stefkova, Katarína; Gierlichs, Lukas; Yates, Brian F.; Ariafard, Alireza; Melen, Rebecca L.

doi:10.1002/anie.202109744

Cited by 17 publications

(5 citation statements)

References 45 publications

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“…3 In 2017, we reported the highly sensitive adduct Ph 2 C(N 2 )B(C 6 F 5 ) 3 4 suggesting that frustrated Lewis pairs (FLPs) might provide an avenue for main group capture of N 2 . While subsequent work by Melen applied borane activation of diazomethanes to organic synthesis, 5,6 we showed that reduction of such adducts generated radicals that effected C–H bond activations 7 and demonstrated that the FLP (C 6 F 5 ) 2 BOP t Bu 2 captured diazomethane to give robust adducts. 8 In addition, we have shown that the corresponding reactions of chloro-diazirene with FLPs effect NN cleavage.…”

mentioning

confidence: 84%

The impact of Lewis acid variation on reactions with di-tert-butyl diazo diesters

Bedi,

Mandal,

Hussain

et al. 2024

Dalton Trans.

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confidence: 84%

The impact of Lewis acid variation on reactions with di-tert-butyl diazo diesters

Bedi,

Mandal,

Hussain

et al. 2024

Dalton Trans.

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“…This was found both experimentally and computationally (Figure 1). 31,34,35 By DFT studies the C-N bond in the boroncoordinated diazo-ester is longer and weaker (1.334 Å) than in the free uncoordinated diazo-ester (1.318 Å). 14 In addition, a shortening of the C−C bond length from 1.470 Å to 1.436 Å was also observed for the O→B adduct.…”

Section: Diazo Activation Using Catalytic B(c6f5)3mentioning

confidence: 99%

Activation of Diazo Compounds by Fluorinated Triarylborane Catalysts

Pramanik

Melen

2023

Synthesis

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The diverse applicability of diazo compounds as versatile reagents has enlarged the chemical toolbox in organic synthesis. Over the past few decades, transition metal-catalyzed diazo compound activation has ignited the classical synthetic methodology via utilizing highly reactive metal carbenoid species. Many reviews have also appeared in the literature which discloses the advantage and disadvantages of metal-catalyzed activation of the diazo compound. Recently, tris(pentafluorophenyl) borane-mediated diazo activation reactions have reconciled this research area due to the potential for mild, environmentally-friendly, metal-free, non-toxic reaction conditions, and the diverse reactivity patterns of boranes towards diazo compounds. In this review, we have discussed the reactivity of the boron-diazo precursor adduct with compounds using catalytic and stoichiometric halogenated triarylboranes and, the mechanism of N2 release from the diazo reagent. This generates the reactive carbene species as a key intermediate which can further be exploited for O−H, N−H, S‒H, and C−H insertions, azide insertion, carbonate transfer, C‒C and C=C bond forming reactions, [2+2] or [2+4] cascade cyclization reactions, annulation reactions, etc. This review is classified by the following themes: 1. Introduction 2. Diazo Activation Using Stoichiometric Boranes 3. Diazo Activation Using Catalytic B(C6F5)3 4. B(C6F5)3 Catalyzed Diazo Activation Reactions 5. Conclusions

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“…In 2021, Melen and co‐workers [61] provided the results of a thorough theoretical and experimental investigation into the highly selective synthesis of N ‐substituted pyrazoles 120 . The reaction of aryl esters 119 and vinyl diazoacetates 114 in the presence of tris(pentafluorophenyl)borane delivered the targeted products 120 in 70%–81% yields.…”

Section: Synthesis Of Pyrazole Derivatives From αβ‐Unsaturated Carbon...mentioning

confidence: 99%

From 2011 to 2022: The development of pyrazole derivatives through the α,β‐unsaturated carbonyl compounds

Sharma,

Singh,

Vaishali

et al. 2023

Journal of Heterocyclic Chem

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The synthesis of pyrazole derivative using α,β‐unsaturated carbonyl compounds has attracted increasing attention of the synthetic organic chemist community. Interestingly, the simplicity of the synthetic method, high reactivity, and ease of incorporating diversity into the desired prototype have contributed a lot toward the exploration of α,β‐unsaturated carbonyl compounds by various research groups. Due to the tremendous pharmacological significance of pyrazole derivatives, their synthesis has been one of the leading research frontiers in recent years. As prime examples, sildenafil, zometapin, Celebrex, and rimonabant have been successfully commercialized in the market to treat various life‐challenging diseases. Considering the great profile of α,β‐unsaturated carbonyl compound in the synthesis of biologically active pyrazole derivatives, this review incorporates contemporary literature (2011–2022) on the synthesis of pyrazole and its derivatives using α,β‐unsaturated carbonyl compound as a starting precursor.

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Tris(pentafluorophenyl)borane‐Catalyzed Carbenium Ion Generation and Autocatalytic Pyrazole Synthesis—A Computational and Experimental Study

Cited by 17 publications

References 45 publications

The impact of Lewis acid variation on reactions with di-tert-butyl diazo diesters

The impact of Lewis acid variation on reactions with di-tert-butyl diazo diesters

Activation of Diazo Compounds by Fluorinated Triarylborane Catalysts

From 2011 to 2022: The development of pyrazole derivatives through the α,β‐unsaturated carbonyl compounds

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