Intramolecular palladium-catalyzed alkene carboalkynylation

Nicolai, Stefano; Swallow, Peter; Waser, Jérôme

doi:10.1016/j.tet.2015.06.030

Cited by 16 publications

(12 citation statements)

References 48 publications

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“…The enolates generated in situ from the conjugate addition of allyl alcohols to α,β‐unsaturated dicarbonyl compounds were also effective as substrates that enabled the synthesis of 3‐benzyltetrahydrofuran derivatives (Scheme ) . In a similar vein, Waser and coworkers also reported a cyclization/cross‐coupling of olefin‐tethered enolates in which bromoalkynylsilane was used as an electrophile (Scheme ) …”

Section: Dicarbofunctionalization Of Tethered Olefins Involving Cyclimentioning

confidence: 99%

Transition Metal‐Catalyzed Dicarbofunctionalization of Unactivated Olefins

Dhungana

Basnet

et al. 2018

The Chemical Record

404

116

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Transition metal (TM)-catalyzed difunctionalization of unactivated olefins with two carbon-based entities is a powerful method to construct complex molecular architectures rapidly from simple and readily available feedstock chemicals. While dicarbofunctionalization of unactivated olefins has a long history typically with the use of either carbon monoxide to intercept C(sp )-[M] (alkyl-TM) species or substrates lacking in β-hydrogen (β-Hs), development of this class of reaction still remains seriously limited due to complications of β-H elimination arising from the in situ-generated C(sp )-[M] intermediates. Over the years, different approaches have been harnessed to suppress β-H elimination, which have led to the development of various types of olefin dicarbofunctionalization reactions even in substrates that generate C(sp )-[M] intermediates bearing β-Hs with a wide range of electrophiles and nucleophiles. In this review, these developments will be discussed both through the lens of historical perspectives as well as the strategies scrutinized over the years to address the issue of β-H elimination. However, this review article by no means is designed to be exhaustive in the field, and is merely presented to provide the readers an overview of the key reaction developments.

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Section: Dicarbofunctionalization Of Tethered Olefins Involving Cyclimentioning

confidence: 99%

Transition Metal‐Catalyzed Dicarbofunctionalization of Unactivated Olefins

Dhungana

Basnet

et al. 2018

The Chemical Record

404

116

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“…A general mechanism of this palladium-catalyzed intramolecular hydrofunctionalization process is shown in Scheme 3. [7] Pd(OAc)2 coordinates to the aminoquinoline directing group and the alkenyl group on the substrate to form a π-alkene complex, which then undergoes nucleopalladation, protodepalladation, and ligand exchange to generate the hydroamination product. Several pertinent mechanistic questions remained outstanding: 1) What is the mechanism of nucleopalladation?…”

Section: Scheme 2 Mechanistic Experiments Scheme 3 General Depictiomentioning

confidence: 99%

“…Substrates 1a-1s were prepared according to adapted literature procedures. [1][2][3][4][5][6][7] according to General Procedure A. Purification using silica gel column chromatography with 1:1 hexane:EtOAc as the eluent gave the product as a light-yellow solid (224 mg, 62% yield). 1 H NMR (600 MHz, CDCl3) δ 10.00 (s, 1H), 8.80 (dd, J = 4.3, 1.6 Hz, 1H), 8.76 (dd, J = 7.4, 1.5 Hz, 1H), 8.16 (dd, J = 8.2, 1.7 Hz, 1H), 7.55-7.49 (m, 2H), 7.46 (dd, J = 8.3, 4.2 Hz, 1H), 5.77 (ddd, J = 6.2, 4.9, 4.0 Hz, 2H), 4.28 (s, 1H), 3.30-3.27 (m, 2H), 3.16 (q, J = 6.7 Hz, 2H), 2.93 (s, 3H), 2.20 (td, J = 7.2, 5.1 Hz, 2H), 1.69-1.63 (m, 2H), 1.57 (dq, J = 10.0, 7.2 Hz, 2H); 13 C NMR (150 MHz, CDCl3) δ 170.0, 148.…”

Section: General Informationmentioning

confidence: 99%

“…Using Pd(OAc)2 as precatalyst and MeCN as solvent, we evaluated a series of carboxylic acid additives (entries [1][2][3][4][5][6] and found that sterically bulky aliphatic acids led to slightly better yields, with 1-AdaCO2H being the best among those tested (entry 1). Another key finding was that polar aprotic solvents, such as MeCN and PhCN, outperformed nonpolar solvents, and that acidic protic solvents, such as HFIP and TFE, led to diminished yields (entries [7][8][9][10][11]. When the reaction temperature was reduced to 80 °C, slightly lower yield was observed, even when the reaction time was extended (entry 12).…”

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confidence: 99%

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Controlling Cyclization Pathways in Palladium(II)-Catalyzed Intramolecular Alkene Hydrofunctionalization via Substrate Directivity

Wang¹,

Li²,

Khanh³

et al. 2020

Preprint

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We report a series of palladium(II)-catalyzed, intramolecular alkene hydrofunctionalization reactions with carbon, nitrogen, and oxygen nucleophiles to form five- and six-membered carbo- and heterocycles. In these reactions, the presence of a proximal bidentate directing group controls the cyclization pathway, dictating the ring size that is generated, even in cases that are disfavored based on Baldwin’s rules and in cases where there is an inherent preference for an alternative pathway. DFT studies shed light on the origins of pathway selectivity in these processes.

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“…Significant advances in this area have been reported by the Waser group ( Scheme 1 ), including Pd-catalyzed alkene aminoalkynylation, as well as oxy- and carbo-alkynylation transformations using ethynylbenziodoxolones (EBX) 5 or aliphatic bromoacetylenes. 6 , 7 Despite these progress, only one example have been demonstrated on internal alkenes so far, impeding its utility to construct more complex, diverse azaheterocycles. Furthermore, reaction conditions need to be tailored for different alkyne precursors in previous methods, limiting the scope of alkyne groups for broad application in organic synthesis and chemical biology.…”

Section: Introductionmentioning

confidence: 99%