<scp>Palladium‐Catalyzed</scp> Oxidative Annulation of <scp>1‐Hydroxy‐<i>o</i>‐Carborane</scp> with Internal Alkynes: Facile Synthesis of <scp>Carborane‐Fused</scp> Oxaboroles<sup>†</sup>

Cheng, Ruofei; Qiu, Zaozao; Xie, Zuowei

doi:10.1002/cjoc.202000307

Cited by 14 publications

(4 citation statements)

References 70 publications

(18 reference statements)

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“…The corresponding carborane-embedded polycyclic molecules have exhibited distinctive properties in terms of Lewis acidity, photophysics and catalysis. [71][72][73][74][75][76][77][78][79][80][81][82][83] Correspondingly, the replacement of the benzene unit in benzoborirene with o-carborane leads to a class of carborane-based 3D analogues of benzoborirene (V in Figure 1). Since the electrons within the carborane cage do not engage in conjugation, [84][85] the borirene unit of 3D benzoborirene exhibits no local aromaticity.…”

Section: Recent Advances In Benzoborirenes and The Carborane-based Th...mentioning

confidence: 99%

“…In recent years, replacing the benzene units in fused polycyclic π‐systems with 3D aromatic carborane units has emerged as a valuable approach in molecular design. The corresponding carborane‐embedded polycyclic molecules have exhibited distinctive properties in terms of Lewis acidity, photophysics and catalysis [71–83] . Correspondingly, the replacement of the benzene unit in benzoborirene with o ‐carborane leads to a class of carborane‐based 3D analogues of benzoborirene ( V in Figure 1).…”

Section: Recent Advances In Benzoborirenes and The Carborane‐based Th...mentioning

confidence: 99%

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Borirenes and Boriranes: Development and Perspectives

Wang,

2023

Chemistry A European J

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Strained compounds constitute a highly topical area of research in chemistry. Borirene and borirane both feature a BC2 three‐membered ring. They can be viewed as the structural analogues of cyclopropane and cyclopropene, where a CH2 unit of the carbonaceous counterparts is replaced with BH, respectively. Indeed, this structural variation introduces numerous intriguing aspects. For instance, borirane and borirene are both Lewis acidic due to the presence of a tricoordinate borane center. In addition, borirene is 2π aromatic according to Hückel's rule. In addition to their ability to form adducts with Lewis bases and the capacity of borirenes to act as ligands in coordination with metals, both borirenes and boriranes exhibit ring‐opening reactivity due to the considerable ring strain. Under specific conditions, coordinated boriranes can even cleave two BC bonds to serve as formal borylene sources (although the reaction mechanisms are quite complex). On the other hand, recent successful syntheses of benzoborienes and their carborane‐based three‐dimensional analogues (also referred to as carborane‐fused boriranes) have introduced novel perspectives to this field. For instance, they display excellent ring‐expanding reactivity, possibly attributed to the boosted ring strain arising from the fusion of borirenes with benzene and boriranes with o‐carborane. Importantly, their applications as valuable “BC2” synthons have become increasingly evident along with the newly disclosed reactivity. Additionally, the boosted Lewis acidity of carborane‐fused boriranes, thanks to the potent electron‐withdrawing effect of o‐carborane, combined with their readiness for ring enlargement, makes them promising candidates as electron‐accepting building blocks in the construction of chemically responsive luminescent materials. This review provides a summary of the synthesis and reactivity of borirene and borirane derivatives, with the aim of encouraging the design of new borierene‐ and borirane‐based molecules and inspiring further exploration of their potential applications.

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Section: Recent Advances In Benzoborirenes and The Carborane-based Th...mentioning

confidence: 99%

Section: Recent Advances In Benzoborirenes and The Carborane‐based Th...mentioning

confidence: 99%

Borirenes and Boriranes: Development and Perspectives

Wang,

2023

Chemistry A European J

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“…C—H activation/alkyne annulation reaction, which is an efficient method for constructing rings in one step, has overviewed great developments in the past decades. [ 35‐45 ] C—H/N—H double activation and alkyne annulation of anilide derivatives [ 46‐49 ] or benzamide derivatives [ 50‐56 ] to form five‐membered indole derivatives or six‐membered isoquinolone derivatives by Rh, Ru, Pd, Ni catalysts were developed by Fagnou, [ 46,50,57 ] Li, [ 58‐60 ] Rovis, [ 51 ] Ackermann, [ 48,53,61 ] Wang, [ 54,62 ] Chatani, [ 63 ] Miura, [ 64 ] Glorius [ 65‐67 ] and others. [ 68‐74 ] As for the construction of functional materials by this method, a pyrido [3,4‐ g ] isoquinoline framework was reported by our group and its fluorescence tuning as well as optical waveguide behavior was studied in 2013.…”

Section: Background and Originality Contentmentioning

confidence: 99%

π‐Extension of Isoindigos (IIDs) through C—H/N—H Activation and Alkyne Annulation^†

et al. 2023

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Comprehensive SummaryIsoindigo (IID) is widely used as organic dye and conjugated unit in opto‐electronic materials. Functionalization of IID to increase its structural complexity is demanding for obtaining diversity properties. Herein, we developed a direct C—H/N—H activation method of IIDs via double alkyne annulations and synthesized π‐extended IIDs with two pairs of 5/7 membered rings. The structure of the π‐extended IIDs was characterized and confirmed by 1H NMR, 13C NMR, HRMS and X ray crystal analysis. Their physical properties were characterized by UV‐vis absorption, cyclic voltammetry and thermogravimetric analysis. The absorption coefficient of the annulated products enhanced significantly compared with the non‐annulated analogue.

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“…[148] Subsequently, Xie reported a palladiumcatalyzed intramolecular B-3 dehydrogenative coupling, [149] acid-assisted iridium-catalyzed B-3/B-6 selective diakenylation of o-carboranes, [150] and recently B-3 selective palladium-catalyzed oxidative annulation of ocarboranes with internal alkynes. [151] Furthermore, Cao [152] and Chi [153] established an NHC ligand-assisted palladium-catalyzed B-3/B-6 selective diarylation of o-carboranes under mild reaction conditions. Recently, Xie reported the B-3 selective iridium-catalyzed B−H amination with ammonia via B−H/N−H dehydrocoupling with broad substrate scope (Scheme 36).…”

Section: Iridium Catalyzed Electrooxidative C−h Activation Was Pionee...mentioning

confidence: 99%

Transition Metal- and Electro-Catalyzed C-H and B-H Activation for the Efficient Synthesis of Carborane Derivatives

Jei¹

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Scheme 6: Manganese-catalyzed access to sillylated imidazoles. Manganese-Catalyzed C−H HydroarylationManganese catalysis has gained ground in selective hydroarylation of alkenes with heterocyclic compounds. The report of Wang and co-workers unveiled a straightforward method for synthesizing aromatic alcohols and ketones via manganese catalysis (Scheme 7a). [39] This report revealed that optimum transformations were achieved in the presence of Me2Zn and ZnBr2 which were responsible for activating the manganese pre-catalyst, thereby forming the more active MnMe(CO)5 complex. In contrast, Ackermann and co-workers reported the manganese catalyzed hydroarylation of ketones with nitrogencontaining heterocycles (Scheme 7b). [40] Furthermore, Glorious recently achieved the formylation of arenes via a manganese(I)/iron(III) sequential catalysis broad substrate scope (Scheme 7a). [41] 1 Introduction 8 Scheme 7. Manganese-catalyzed addition of carbonyls to arenes and heterocycles Manganese catalysis has proven resourceful for functionalizing nitrogencontaining heterocycles. The groups of Ackermann and Wang made enormous contributions to this achievement. Ackermann reported the efficient C-2 selective aminocarbonylation of indoles and pyrroles via manganese catalysis. The reaction proceeded successfully without an additive with industrially relevant imines and isocyanates as reaction partners. The same group also realized the C-2 selective C−H activation of indoles with imines via a manganese(I) regime (Scheme 8a). [42] Wang, in an extension unraveled a chemo-selective coupling of ketones with imines to furnish benzylic amines (Scheme 8b). [43] 1 Introduction 9 Scheme 8. Manganese-catalyzed addition of imines and isocyanates to arenes and heterocycles The manganese(I)-catalyzed C−H hydroarylation was not limited to carbonyl compounds but was expanded to include alkenes and alkynes. Wang and coworkers demonstrated this concept in two reports, with the manganesecatalyzed selective alkenylation of arenes with terminal alkynes. [44] In one account, they established an environmentally-benign protocol to access highly functionalized molecules via a base-promoted mechanism. Further, they developed a reliable regime to construct synthetically relevant nitriles from imidates and terminal alkynes. Interestingly, high regio-selectivity was achieved in both cases (Scheme 9a). Also, Ackermann reported Brønsted acid-assisted C-2 selective alkenylation of indole derivatives with propargylic carbonates under manganese(I) catalysis. This regime enabled the successful synthesis of target molecules within a short reaction time facilitated by a flow 1 Introduction 10 setup (Scheme 9b). [45] In addition, Lei and Li extended the scope of manganese(I) catalyzed hydroarylation of indole derivatives to internal alkynes with high regioselectivity (Scheme 9c). [46] Scheme 9. Manganese-catalyzed C−H activation for hydroarylations.In addition to terminal alkynes, manganese(I) catalysis has proven beneficial for the selective alkylation of electron-defic...

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Palladium‐Catalyzed Oxidative Annulation of 1‐Hydroxy‐o‐Carborane with Internal Alkynes: Facile Synthesis of Carborane‐Fused Oxaboroles^†

Cited by 14 publications

References 70 publications

Borirenes and Boriranes: Development and Perspectives

Borirenes and Boriranes: Development and Perspectives

π‐Extension of Isoindigos (IIDs) through C—H/N—H Activation and Alkyne Annulation^†

Transition Metal- and Electro-Catalyzed C-H and B-H Activation for the Efficient Synthesis of Carborane Derivatives

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Palladium‐Catalyzed Oxidative Annulation of 1‐Hydroxy‐o‐Carborane with Internal Alkynes: Facile Synthesis of Carborane‐Fused Oxaboroles†

Cited by 14 publications

References 70 publications

Borirenes and Boriranes: Development and Perspectives

Borirenes and Boriranes: Development and Perspectives

π‐Extension of Isoindigos (IIDs) through C—H/N—H Activation and Alkyne Annulation†

Transition Metal- and Electro-Catalyzed C-H and B-H Activation for the Efficient Synthesis of Carborane Derivatives

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Palladium‐Catalyzed Oxidative Annulation of 1‐Hydroxy‐o‐Carborane with Internal Alkynes: Facile Synthesis of Carborane‐Fused Oxaboroles^†

π‐Extension of Isoindigos (IIDs) through C—H/N—H Activation and Alkyne Annulation^†