Regiodivergent Enantioselective γ-Additions of Oxazolones to 2,3-Butadienoates Catalyzed by Phosphines: Synthesis of α,α-Disubstituted α-Amino Acids and <i>N</i>,<i>O</i>-Acetal Derivatives

Wang, Tianli; Yu, Zhaoyuan; Hoon, Ding Long; Phee, Claire Yan; Lan, Yu; Lü, Yixin

doi:10.1021/jacs.5b10524

Cited by 149 publications

(44 citation statements)

References 91 publications

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“…In another example, ac ollaboration between the Lu group and our own reported phosphine-catalyzed regiodivergent enantioselective C-2-and C-4-selective g additions of oxazolones to 2,3-butadienoates ( Figure 18). [26] With the use of 2aryl-4-alkyl-substituted oxazolones as donors, the C-4-selective g addition occurredt oy ield highly enantiomerically enriched 4,4-disubstituted oxazolones. The use of 2-alkyl-4-aryl-substituted oxazolones as pronucleophiles led exclusively to C-2-selective g addition to the 2,3-butadienoates.…”

Section: Electrophilic Addition With Zwitterionic Phosphoniummentioning

confidence: 99%

Mechanism of Phosphine‐Catalyzed Allene Coupling Reactions: Advances in Theoretical Investigations

Cui

Shan

Zhang

et al. 2018

Chemistry An Asian Journal

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Organocatalysis has emerged as an effective strategy for chemical synthesis. Within this area, phosphine-catalyzed coupling reactions have attracted considerable attention because of their versatility and wide range of applications in the construction of new C-C bonds. Recently, various experimental studies on the phosphine-catalyzed coupling reaction of allenes have been reported, and mechanistic and computational studies have also progressed considerably. As a nucleophile, phosphine can react with an allene to form a zwitterionic phosphoniopropenide intermediate. After stepwise cycloaddition and proton transfer, the phosphine catalyst can be regenerated by C-P bond cleavage. Alternatively, the zwitterionic phosphoniopropenide intermediate could also be protonated by a Brønsted acid to generate a phosphonium intermediate, which can be used to construct new C-C bonds by electrophilic addition. In this review, we have summarized details of mechanistic studies of phosphine-catalyzed allene coupling reactions that follow these two reaction modes. In addition to detailing the reaction pathway, the regioselectivity and diastereoselectivity of the phosphine-catalyzed allene coupling reaction are also discussed in this review.

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Section: Electrophilic Addition With Zwitterionic Phosphoniummentioning

confidence: 99%

Mechanism of Phosphine‐Catalyzed Allene Coupling Reactions: Advances in Theoretical Investigations

Cui

Shan

Zhang

et al. 2018

Chemistry An Asian Journal

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“…6 The only example of S N Ar-type reactions with oxazolones is the addition to 2-nitroarenes, which undergoes subsequent cyclization with the nitro functional group to give indazole products (eqn 3) . 7 Though the reaction leads to a different product, it suggests that oxazolone enolate might be a competent nucleophile in the addition to perfluoroarenes.…”

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confidence: 99%

“…We were pleased to see that even the substituted oxazolone enolate underwent selective C4-addition to give the desired amino acids, rather than C2-addition which has been observed for substituted oxazolones. 6, 13 However, in order to be able to derivatize in the second step, we found it necessary to utilize DIPEA as the base. Perfluoroarylated amino acid esters were derived from alanine, valine, methionine, and phenylalanine in good yield (6a–d) .…”

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confidence: 99%

Polyfluoroarylation of oxazolones: access to non-natural fluorinated amino acids

Teegardin

Weaver

2017

Chem. Commun.

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Herein, conditions are provided for the formation and use of the oxazolone enolate for the nucleophilic substitution of highly fluorinated (hetero) arenes, which after unmasking yield highly fluorinated non-natural amino acids and derivatives. In addition, the properties and chemical behavior of this new class of amino acids are explored. The utility is demonstrated in the one pot synthesis of medicinally relevant 2-aminohydantoins.

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“…In addition, high enantioselectivity and/or diastereoselectivity can be achieved by the introduction of asymmetric trisubstituted phosphines 46–50 . As a result of the broad application of this catalyst in the construction of five-membered carbocycles, the mechanism of this [3 + 2] cycloaddition has attracted considerable attention by both theoretical and experimental chemists 34, 51–54 .…”

Section: Introductionmentioning

confidence: 99%

From Mechanistic Study to Chiral Catalyst Optimization: Theoretical Insight into Binaphthophosphepine-catalyzed Asymmetric Intramolecular [3 + 2] Cycloaddition

Duan

Zhu

et al. 2017

Sci Rep

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Density functional M11 was used to study the mechanism and enantioselectivity of a binaphthophosphepine-catalyzed intramolecular [3 + 2] cycloaddition reaction. The computational results revealed that this reaction proceeds through nucleophilic addition of the phosphine catalyst to the allene, which yields a zwitterionic phosphonium intermediate. The subsequent stepwise [3 + 2] annulation process, which starts with the intramolecular nucleophilic addition of the allenoate moiety to the electron-deficient olefin group, determines the enantioselectivity of the reaction. This step is followed by a ring-closing reaction and water-assisted proton-transfer process to afford the final product with concomitant regeneration of the phosphine catalyst. Theoretical predictions of the enantioselectivity for various phosphine catalysts were consistent with experimental observations, and 2D contour maps played an important role in explaining the origin of the enantioselectivity. Moreover, on the basis of our theoretical study, new binaphthophosphepine catalysts were designed and that are expecting to afford higher enantioselectivity in this cycloaddition reaction.

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Regiodivergent Enantioselective γ-Additions of Oxazolones to 2,3-Butadienoates Catalyzed by Phosphines: Synthesis of α,α-Disubstituted α-Amino Acids and N,O-Acetal Derivatives

Cited by 149 publications

References 91 publications

Mechanism of Phosphine‐Catalyzed Allene Coupling Reactions: Advances in Theoretical Investigations

Mechanism of Phosphine‐Catalyzed Allene Coupling Reactions: Advances in Theoretical Investigations

Polyfluoroarylation of oxazolones: access to non-natural fluorinated amino acids

From Mechanistic Study to Chiral Catalyst Optimization: Theoretical Insight into Binaphthophosphepine-catalyzed Asymmetric Intramolecular [3 + 2] Cycloaddition

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