Quadruple Role of Pd Catalyst in Domino Reaction Involving Aryl to Alkyl 1,5‐Pd Migration to Access 1,9‐Bridged Triptycenes

Iwata, Tomonori; Kumagai, Satoru; Yoshinaga, Tatsuro; Hanada, Masato; Shiota, Yoshihito; Yoshizawa, Kazunari; Shindo, Mitsuru

doi:10.1002/chem.202101728

Cited by 9 publications

(4 citation statements)

References 77 publications

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“…[22] During their consequent study on the same coupling of 9-methoxyl analogue 46 b, unexpectedly, 1,9-bridged triptycene 48 b was obtained selectively, instead the formation of expected triaryltriptycene 47 b was not detected (Scheme 12b). [23] Along with the reaction condition experiments, the authors found that the formation of bromo- Based on these observations, the authors proposed a plausible catalytic cycle account for the formation of 48, in which the palladium catalyst might play a quadruple role in the whole process. According to deuterium labeling experiments, aryl-to-alkyl 1,5-palladium migration (from 49 to 51) might proceeded through either σ-bond metathesis via a palladium(II) transition state 50 a or oxidative addition via a palladium(IV) intermediate 50 b (vide supra) with hydrogen atom completely retained.…”

Section: Aryl-to-alkyl Migrationmentioning

confidence: 93%

“…In 2019, Shindo and coworkers reported a palladium‐catalyzed triple Suzuki coupling of 9‐hydroxy‐1,8,13‐tribromotriptycene 46 a (Scheme 12a) [22] . During their consequent study on the same coupling of 9‐methoxyl analogue 46 b , unexpectedly, 1,9‐bridged triptycene 48 b was obtained selectively, instead the formation of expected triaryltriptycene 47 b was not detected (Scheme 12b) [23] . Along with the reaction condition experiments, the authors found that the formation of bromotriptycene 49 b could be formally suppressed by extending the reaction time, while the yield of 48 b was increased, which suggested 49 b was a reaction intermediate for 48 b .…”

Section: 5‐palladium Migration Reactionsmentioning

confidence: 99%

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Taming the Selective C−H Bond Activation through 1,5‐Palladium Migration

Fang,

Ding,

Huang

2024

ChemCatChem

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“Through space” metal/hydrogen shift constitutes one of the efficient elementary step in organometallic chemistry to achieve selective remote C‐H bond functionalization. Compared with the relatively extensive exploration on 1,4‐palladium migration, the processes on corresponding 1,5‐palladium translocation are far less explored. Based on our understanding on related research areas, we summarized the advances achieved on remote C‐H bond activation through a key step of 1,5‐palladium migration in this minireview. The background, reaction scope, and more importantly, the mechanistic rationale of each transformation was discussed. We hope by reading through this minireview, one could get a general perspective on direct C‐H bond activation via 1,5‐palladium/hydrogen shift, and could understand why such a process is less common when compared with the process going through 1,4‐palladium/hydrogen migration, and eventually could be inspired to develop practical ways for the synthesis of valuable molecules, which could not be prepared easily through other traditional approach.

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Section: Aryl-to-alkyl Migrationmentioning

confidence: 93%

Section: 5‐palladium Migration Reactionsmentioning

confidence: 99%

Taming the Selective C−H Bond Activation through 1,5‐Palladium Migration

Fang,

Ding,

Huang

2024

ChemCatChem

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“…More interestingly, the silicon atom seems to play an indispensable role for this migration to occur, since the reaction of a carbon analogue failed to give the desired product under otherwise identical conditions [5f] . Very recently, Iwata and Shindo also described an aryl to alkyl 1,5‐palladium migration process, and applied this strategy for 1,9‐bridged triptycene synthesis [5g] . Despite of these advances, in view of the significance for selective remote C−H bond activation, the discovery of other type 1,5‐palladium migration events are still of great value.…”

Section: Introductionmentioning

confidence: 99%

Alkyne Insertion Enabled Vinyl to Acyl 1,5‐Palladium Migration: Rapid Access to Substituted 5‐Membered‐Dihydrobenzofurans and Indolines

Ding

et al. 2023

Angewandte Chemie

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“Through space” palladium/hydrogen shift is an efficient strategy to achieve selective functionalization of a specific remote C−H bond. Compared with relatively extensive exploited 1,4‐palladium migration process, the relevant 1,5‐Pd/H shift was far less investigated. We herein report a novel 1,5‐Pd/H shift pattern between a vinyl and an acyl group. Through the pattern, rapid access to 5‐membered‐dihydrobenzofuran and indoline derivatives has been achieved. Further studies have unveiled an unprecedented trifunctionalization (vinylation, alkynylation and amination) of a phenyl ring through 1,5‐palladium migration relayed decarbonylative Catellani type reaction. A series of mechanistic investigations and DFT calculations have provided insights into the reaction pathway. Notably, it was unveiled that the 1,5‐palladium migration in our case prefers a stepwise mechanism involving a PdIV intermediate.

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“…The 1,2-Pd II shift via a β-H elimination and reinsertion sequence, 1,4-Pd II shift, and, to a lesser extent, the 1,5-Pd II migration − via C–H activation are well-established. However, to the best of our knowledge, there is only one example of 1,3-Pd II shift reported by Wolfe .…”

mentioning

confidence: 96%

Quaternary Carbon Editing Enabled by Sequential Palladium Migration

Wu,

Fujii,

Wang

et al. 2024

J. Am. Chem. Soc.

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Peripheral functionalization of a quaternary carbon via C(sp 3 )−H bond activation has made significant progress in recent years. However, direct editing of a quaternary carbon through Csp 3 −Csp 3 bond cleavage and refunctionalization of nonstrained acyclic molecules remain underexploited. Herein we report a reaction in which a methyl group attached to a quaternary carbon is shifted to its neighboring secondary carbon with concurrent oxidation of the quaternary C−C single bond to the C�C double bond. Specifically, morpholinyl amide of 2,2-dimethyl alkanoic acids is converted to 2-methylene-3-methyl alkanoic acid derivatives in the presence of a catalytic amount of palladium acetate, Selectfluor and sodium carbonate. Control experiments suggest that the reaction proceeds via a sequence of selective C(sp 3 )−H activation of the methyl group, oxidation of the resulting C(sp 3 )− Pd II to Pd IV intermediate followed by unprecedented 1,3-Pd IV migration, 1,2-methyl/Pd IV dyotropic rearrangement and finally, β− Hydride elimination. In this domino process, palladium migrates successively from the primary to the secondary and finally to the quaternary carbon, leading to the concurrent functionalization of a primary, a secondary, and a quaternary carbon.

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Quadruple Role of Pd Catalyst in Domino Reaction Involving Aryl to Alkyl 1,5‐Pd Migration to Access 1,9‐Bridged Triptycenes

Cited by 9 publications

References 77 publications

Taming the Selective C−H Bond Activation through 1,5‐Palladium Migration

Taming the Selective C−H Bond Activation through 1,5‐Palladium Migration

Alkyne Insertion Enabled Vinyl to Acyl 1,5‐Palladium Migration: Rapid Access to Substituted 5‐Membered‐Dihydrobenzofurans and Indolines

Quaternary Carbon Editing Enabled by Sequential Palladium Migration

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