Cyclocarbopalladation as a Key Step in Cascade Reactions: Recent Developments

Blouin, Sarah; Blond, Gaëlle; Donnard, Morgan; Gulea, Mihaela; Suffert, J.

doi:10.1055/s-0036-1588708

Cited by 28 publications

(1 citation statement)

References 73 publications

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“…Malonate deprotonation by sodium hydride, followed by allylation with 2,3-dibromopropene, gave the monoallylated product. Further deprotonation by sodium hydride and treatment with excess propargyl bromide Previous work from our group [15,16] demonstrated that this type of cascade can indeed be used to synthesize 7,8 systems (8, Figure 1b), and indeed carbopalladation/coupling/ electrocyclisation sequences are generally well-established [17][18][19][20]. However, we aimed to avoid the use of a toxic organotin coupling partner as had been employed in our previous work [15,16] by switching to an untested Suzuki/8π strategy.…”

Section: Synthesis Of 56-fused Systems By Bromoenynamide Carbopallada...mentioning

confidence: 99%

Synthetic Study toward Triterpenes from the Schisandraceae Family of Natural Products

Kravljanac

Anderson

2023

Molecules

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Triterpenoid natural products from the Schisandraceae family have long presented a significant synthetic challenge. Lancifodilactone I, a member of the family not previously synthesized, was identified as a key natural product target, from which many other members could be synthesized. We envisaged that the core ring system of lancifodilactone I could be accessed by a strategy involving palladium-catalysed cascade cyclisation of a bromoenynamide, via carbopalladation, Suzuki coupling and 8π-electrocyclisation, to synthesize the core 7,8-fused ring system. Exploration of this strategy on model systems resulted in efficient syntheses of 5,6- and 5,8-fused systems in high yields, which represent the first such cyclisation where the ynamide nitrogen atom is ‘external’ to the forming ring system. The enamide functionality resident in the cascade cyclisation product was found to be less nucleophilic than the accompanying tri-/tetrasubstituted alkene(s), enabling regioselective oxidations. Application of this strategy to 7,6-, and 7,8-fused systems, and ultimately the ‘real’ substrate, was ultimately thwarted by the difficulty of 7-membered ring closure, leading to side product formation. Nevertheless, a tandem bromoenynamide carbopalladation, Suzuki coupling and 6/8π-electrocyclisation was shown to be a highly efficient tactic for the formation of bicyclic enamides, which may find applications in other synthetic contexts.

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Section: Synthesis Of 56-fused Systems By Bromoenynamide Carbopallada...mentioning

confidence: 99%

Synthetic Study toward Triterpenes from the Schisandraceae Family of Natural Products

Kravljanac

Anderson

2023

Molecules

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Ruthenium‐Catalyzed Three‐Component Alkylation: A Tandem Approach to the Synthesis of Nonsymmetric N,N‐Dialkyl Acyl Hydrazides with Alcohols

et al. 2021

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The borrowing hydrogen strategy has been applied in the synthesis of nonsymmetric N,N‐dialkylated acyl hydrazides via a tandem three‐component reaction catalyzed by a phosphine free diaminocyclopentadienone ruthenium tricarbonyl complex. This strategy represents the first direct one‐pot approach to nonsymmetric functionalized acyl hydrazides. Different aromatic acyl hydrazides underwent dialkylation with a variety of primary or secondary alcohols and methanol or ethanol as alkylating agents in mild reaction conditions and good yields. Deuterium labelling experiments suggested that the primary or secondary alcohol was the hydrogen source in this tandem process. DFT calculations show that the combination of the tandem mixed product cannot be perfectly explained neither structurally nor electronically, but might be dependent of the physical state of the aldehyde or ketone intermediate (gaz vs. liquid) at the reaction temperature.

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Pd‐Catalyzed One‐Pot Sequential Sonogashira Coupling and Dual Annulations Cascade for the Synthesis of Benzofuro[3,2‐c]‐Triazalo/Pyrrolo‐Quinolines

et al. 2022

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Palladium-catalyzed coupling reaction followed by dual annulation has been achieved for the synthesis of various triazolo/pyrrolo fused benzofuro-quinolines from readily available starting materials. The developed protocol proceeds through palladium-catalyzed Sonogashira coupling, benzannulation followed by CÀ H activation triggered second annulation reaction cascades in a single pot. In particular, the polycyclic compound formed by this method consists of three different heterocyclic structures: benzofuran, quinoline, and triazole/ pyrrole. The method provides simple access to obtain a range of fused benzofurotriazalo/pyrroloquinolines in good to moderate yields.

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Cyclocarbopalladation as a Key Step in Cascade Reactions: Recent Developments

Cited by 28 publications

References 73 publications

Synthetic Study toward Triterpenes from the Schisandraceae Family of Natural Products

Synthetic Study toward Triterpenes from the Schisandraceae Family of Natural Products

Ruthenium‐Catalyzed Three‐Component Alkylation: A Tandem Approach to the Synthesis of Nonsymmetric N,N‐Dialkyl Acyl Hydrazides with Alcohols

Pd‐Catalyzed One‐Pot Sequential Sonogashira Coupling and Dual Annulations Cascade for the Synthesis of Benzofuro[3,2‐c]‐Triazalo/Pyrrolo‐Quinolines

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