Me3(OMe)tBuXPhos: A Surrogate Ligand for Me4tBuXPhos in Palladium-Catalyzed C–N and C–O Bond-Forming Reactions

Ueda, Satoshi; Ali, Siraj Z.; Fors, Brett P.; Buchwald, Stephen L.

doi:10.1021/jo202537e

Cited by 53 publications

(28 citation statements)

References 11 publications

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“…Replacing the 6‐methoxyl group of the ligand with a methyl substituent ( L5 and L6 ) led to improved yields, indicating that ligand rigidity may be important in this transformation (entry 5, 6) . After further evaluation of ligands possessing a trimethylmethoxy‐substituted top ring ( L7 and L8 ), a novel biarylphosphine ligand L8 was found to provide 2 a in moderate combined yield (58 %) though still with poor regioselectivity (1.8:1; entry 7, 8).…”

Section: Figurementioning

confidence: 99%

Palladium‐Catalyzed Fluorination of Cyclic Vinyl Triflates: Effect of TESCF₃ as an Additive

Takada

Buchwald

2016

Angewandte Chemie

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A method for the palladium-catalyzed fluorination of cyclic vinyl triflates has been developed. As with several previous palladium-catalyzed fluorination reactions using fluoride salts, controlling the regioselectivity was nontrivial and presented a challenge in developing a practical synthetic procedure. The addition of triethyl(trifluoromethyl)silane (TESCF 3 ) was found to effectively address this problem and resulted in dramatically improved regioselectivities in this palladiumcatalyzed fluorination reaction. This discovery, along with the use of a new biarylphosphine ligand, allowed for the development of an efficient and highly regioselective protocol for the fluorination of vinyl triflates. This method is compatible with a range of sensitive functional groups and provides access to cyclic (five, six, and seven-membered) vinyl fluorides Graphical AbstractA technique for the palladium-catalyzed fluorination of cyclic vinyl triflates has been developed. The reaction exhibited good functional group tolerance and proceeded efficiently for five, six and seven-membered vinyl triflate substrates, as well as a few acyclic substrates. The addition of Correspondence to: Stephen L. Buchwald. Supporting information for this article is given via a link at the end of the document. (Figure 1). [1,2] The alkenyl fluoride group resembles an amide linkage in terms of both steric demand and charge distribution, [3] but fluoroalkenes exhibit substantially enhanced stability towards hydrolysis compared to amides. Moreover, in contrast to amides, which often exist as equilibrating s-cis and s-trans rotamers, fluoroalkenes are configurationally stable. As a result, they have been investigated as amide bioisosteres with improved lipophilicity and metabolic stability in pharmaceutical applications and as tools for probing the conformational properties of biologically active amides. [4] In addition to these applications, fluoroalkenes also serve as versatile starting materials for a variety of transformations, including the Diels-Alder reaction, [5a] cyclopropanation, [5b,5c] and epoxidation, [5d] allowing for the construction of other classes of fluorine-containing molecules. HHS Public AccessDespite considerable potential, fluoroalkenes are underutilized due to challenges in their synthesis. Current approaches for their preparation generally require multistep functional group manipulations or the use of harsh reaction conditions, which limit the functional group compatibility of these techniques. [6][7][8][9][10][11] The development of a mild and general method for fluoroalkene synthesis would therefore be highly desirable. Due to the challenge of preparing suitable precursors, cyclic fluoroalkenes are particularly difficult to access using existing methods, and new methods that provide access to these compounds would be especially useful.In this context, the palladium-catalyzed coupling of cyclic vinyl triflates with simple metal fluoride salts represents a particularly attractive strategy to access fluoroalkenes....

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Section: Figurementioning

confidence: 99%

Palladium‐Catalyzed Fluorination of Cyclic Vinyl Triflates: Effect of TESCF₃ as an Additive

Takada

Buchwald

2016

Angewandte Chemie

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“…Zhang et al [32] studied amination of carbon-hydrogen bond under the existence of palladium catalyst, which provides versatile approaches to ammoniate aromatic ring. Buchwald et al [33] studied the formation mechanism of carbon-nitrogen and carbon-oxygen bond which catalyzed by palladium. Takeda et al [34] studied palladiumcatalyzed reactions between ethylenes and carbazole.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study of Reaction Mechanism between N,N-Dimethyl acrylamide and Carbazole Derivatives Catalyzed by Palladium(II)

Jing¹,

Zhu²,

Su³

et al. 2017

Asian J. Chem.

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The reaction mechanism between N,N-dimethyl acrylamide and carbazole derivatives catalyzed by palladium acetate has been investigated by using density functional theory (DFT) with M06 functional. The computational results indicate that the reaction without catalyst reacts via one pathway with a high energy barrier of 254.57 kJ mol -1 . While the reaction can happen through two approaches to generate the same product with the existence of palladium acetate catalysis. Furthermore, the catalyst is better to depart from the product as a whole part. And the determining step of dominant pathway in the Pd-catalyzed reaction is the formation of C-N bond which has an energy barrier of 137.91 kJ mol -1 . As a result, palladium catalyst not only changes the reaction mechanism, but also decreases the energy barrier significantly which stimulated the reaction well. This study illustrates the reaction mechanism and has a guiding significance for new catalysts designing. Asian Journal of Chemistry; Vol. 29, No. 7 (2017), 1487-1491 Pd(II) center coordinated with styrene and subsequent activated ethylene and finally the acetic acid deprives from the product one by one as well as the palladium atom.In a reaction the palladium catalyst can deprive from product not only as separated acetic acid molecule and palladium atom but also a whole part. To make the reaction mechanism between N,N-dimethyl acrylamide and carbazole derivatives, this article illustrated a theoretical study on Pd-catalyzed reaction between N,N-dimethyl acrylamide and carbazole derivatives. COMPUTATIONAL METHODSGaussian 09 program [35] was employed for all calculations which based on the fundamental laws of quantum mechanism give numerous of important information. At the very beginning, we studied the reaction with the hybrid B3LYP [36] functional and the effective core potential basis set LANL2DZ [37] for metal element and 6-31G** [38-41] basis set for non-metal elements. Geometries of every molecules are optimized by M06 [42] functional with LANL2TZ [37,43] basis set for palladium atom and 6-31G** basis set for other nonmetal atoms. In this paper, vibration frequencies were calculated to get thermal corrections and identify transition states of every stationary point and the natural bond orbital (NBO) [44,45] analysis was applied to evaluate the Wiberg

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“…Replacing the 6-methoxyl group of the ligand with a methyl substituent ( L5 and L6 ) led to improved yields, indicating that ligand rigidity may be important in this transformation (entry 5–6). [13] After further evaluation of ligands possessing a trimethylmethoxy-substituted top ring ( L7 and L8 ), [14] a novel biarylphosphine ligand L8 was found to provide 2a in moderate combined yield (58%) though still with poor regioselectivity (1.8:1) (entry 7–8).…”

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confidence: 99%

Palladium‐Catalyzed Fluorination of Cyclic Vinyl Triflates: Effect of TESCF₃ as an Additive

Takada

Buchwald

2016

Angew Chem Int Ed

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Me₃(OMe)tBuXPhos: A Surrogate Ligand for Me₄tBuXPhos in Palladium-Catalyzed C–N and C–O Bond-Forming Reactions

Cited by 53 publications

References 11 publications

Palladium‐Catalyzed Fluorination of Cyclic Vinyl Triflates: Effect of TESCF₃ as an Additive

Palladium‐Catalyzed Fluorination of Cyclic Vinyl Triflates: Effect of TESCF₃ as an Additive

Theoretical Study of Reaction Mechanism between N,N-Dimethyl acrylamide and Carbazole Derivatives Catalyzed by Palladium(II)

Palladium‐Catalyzed Fluorination of Cyclic Vinyl Triflates: Effect of TESCF₃ as an Additive

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Me3(OMe)tBuXPhos: A Surrogate Ligand for Me4tBuXPhos in Palladium-Catalyzed C–N and C–O Bond-Forming Reactions

Cited by 53 publications

References 11 publications

Palladium‐Catalyzed Fluorination of Cyclic Vinyl Triflates: Effect of TESCF3 as an Additive

Palladium‐Catalyzed Fluorination of Cyclic Vinyl Triflates: Effect of TESCF3 as an Additive

Theoretical Study of Reaction Mechanism between N,N-Dimethyl acrylamide and Carbazole Derivatives Catalyzed by Palladium(II)

Palladium‐Catalyzed Fluorination of Cyclic Vinyl Triflates: Effect of TESCF3 as an Additive

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Me₃(OMe)tBuXPhos: A Surrogate Ligand for Me₄tBuXPhos in Palladium-Catalyzed C–N and C–O Bond-Forming Reactions

Palladium‐Catalyzed Fluorination of Cyclic Vinyl Triflates: Effect of TESCF₃ as an Additive

Palladium‐Catalyzed Fluorination of Cyclic Vinyl Triflates: Effect of TESCF₃ as an Additive

Palladium‐Catalyzed Fluorination of Cyclic Vinyl Triflates: Effect of TESCF₃ as an Additive