Stereoselective syntheses of α,β-unsaturated γ-amino esters through phosphine-catalyzed γ-umpolung additions of sulfonamides to γ-substituted allenoates

Zhou, Qingfa; Zhang, Kui; Kwon, Ohyun

doi:10.1016/j.tetlet.2015.01.120

Cited by 21 publications

(7 citation statements)

References 62 publications

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“…Phosphine-catalyzed γ-addition of activated allene 7 bearing an electron-withdrawing ester group afforded the desired product 8 in excellent yield at room temperature (Scheme 8a). 26 As expected, weakly activated allenes showed very low reactivity in this Lewis base-catalyzed γ-addition reaction. Addition of phenylallene 9 with TsNH 2 afforded 10 in less than 3% yield at 100 °C, leaving untouched starting material in the reaction (Scheme 8b).…”

Section: ■ Results and Discussionsupporting

confidence: 64%

Lewis Base-Catalyzed Amino-Acylation of Arylallenes via C–N Bond Cleavage: Reaction Development and Mechanistic Studies

Zhang

Yang

et al. 2020

ACS Catal.

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Lewis base-catalyzed transformations of allenes have received much attention over the last decades. However, this type of reaction has so far been limited to activated allenes bearing an electron-withdrawing group. On the other hand, cleavage of an amide C–N bond to forge other chemical bonds has been widely reported but restricted to low atom economy due to the waste of the amine moiety of amides. We initiated a project of metal-catalyzed amino-acylation of allenes via cleavage of amide C–N bonds. Surprisingly, an amino-acylation of weakly activated aryl allenes was discovered via Lewis base catalysis, providing 2-methyl-3-aroylindole products, “privileged structures” in drug discovery. This is a unique example of Lewis base catalysis of weakly activated allenes, which was not reported yet. Extensive experimental and computational studies have been conducted to provide insight into the reaction mechanism. The nucleophilic addition of Lewis base catalyst to aryl allene is the rate-limiting step. A challenging [1,3]-proton transfer is realized by nitrogen anion intermediate assisted sequential [1,4]- and [1,6]-proton transfer in the reaction pathway.

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Section: ■ Results and Discussionsupporting

confidence: 64%

Lewis Base-Catalyzed Amino-Acylation of Arylallenes via C–N Bond Cleavage: Reaction Development and Mechanistic Studies

Zhang

Yang

et al. 2020

ACS Catal.

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“…In 2015, Kwon and co-workers reported the stereoselective syntheses of α , β -unsaturated γ -amino esters via phosphine-catalyzed γ -umpolung additions of sulfonamides to γ -substituted allenoates (Scheme 124). 197 With 20 mol % of Ph 3 P as the catalyst, a number of sulfonamides with various substituents appended to the benzene ring underwent the addition reaction in Et 2 O at room temperature to give the desired products in good to excellent yields (81–98%) with E/Z stereoselectivities ranging from 89:11 to 99:1. A variety of γ -substituted allenoates were also suitable for the reaction.…”

Section: Nucleophilic Phosphine Catalysis Of Allenesmentioning

confidence: 99%

Phosphine Organocatalysis

et al. 2018

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The hallmark of nucleophilic phosphine catalysis is the initial nucleophilic addition of a phosphine to an electrophilic starting material, producing a reactive zwitterionic intermediate, generally under mild conditions. In this Review, we classify nucleophilic phosphine catalysis reactions in terms of their electrophilic components. In the majority of cases, these electrophiles possess carbon–carbon multiple bonds: alkenes (section 2), allenes (section 3), alkynes (section 4), and Morita–Baylis–Hillman (MBH) alcohol derivatives (MBHADs; section 5). Within each of these sections, the reactions are compiled based on the nature of the second starting material—nucleophiles, dinucleophiles, electrophiles, and electrophile–nucleophiles. Nucleophilic phosphine catalysis reactions that occur via the initial addition to starting materials that do not possess carbon–carbon multiple bonds are collated in section 6. Although not catalytic in the phosphine, the formation of ylides through the nucleophilic addition of phosphines to carbon–carbon multiple bond–containing compounds is intimately related to the catalysis and is discussed in section 7. Finally, section 8 compiles miscellaneous topics, including annulations of the Hüisgen zwitterion, phosphine-mediated reductions, iminophosphorane organocatalysis, and catalytic variants of classical phosphine oxide–generating reactions.

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“…Significantly, nucleophilic phosphine catalysis has been established as a reliable platform for the efficient assembly of a variety of cyclic products from simple building blocks . In particular, activated allenes subjected to nucleophilic phosphine catalysis conditions exhibit diverse reactivity toward electrophilic reagents .…”

Section: Introductionmentioning

confidence: 99%

“…[8] Significantly, nucleophilic phosphine catalysis has been established as a reliable platform for the efficient assembly of a variety of cyclic products from simple building blocks. [9][10][11][12] In particular, activated allenes subjected to nucleophilic phosphine catalysis conditions exhibit diverse reactivity toward electrophilic reagents. [13,14] These electron-deficient allenes can function as two-, three-, or four-carbon synthons when reacting with a variety of electrophilic reagents undergoing [3 1 2], [3 1 2 1 3], [3 1 3], [4 1 2], [4 1 3], or [2 1 4] annulations (shown in Scheme 1).…”

mentioning

confidence: 99%

Mechanisms of phosphine‐catalyzed [4 + 3] annulation of allenoates with C, N‐cyclic azomethine imines: A DFT investigation

Zhu

Guo

et al. 2018

Int J of Quantum Chemistry

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In this article, mechanisms of phosphine‐catalyzed [4 + 3] annulation of allenoates with C, N‐cyclic azomethine imines have been investigated using density functional theory. The catalytic cycle for the title reaction consists of five steps. Namely, the first step is the nucleophilic addition of phosphine catalyst, the second one is the CC bond formation, the third one is the proton transfer process, and the next one is the ring‐closure process, the last one is dissociation of the catalyst and the product generation. The calculated results indicate that the nucleophilic addition of phosphine catalyst is rate‐determining. With the use of Cat as the chiral catalyst, optically active products were obtained in good yields with excellent enantioselectivities while the CC bond formation is stereoselectivity‐determining. Furthermore, the theoretically predicted the main product is SS configuration, which is in good agreement with the experimental results. The special role of the catalysts and origin of stereoselectivity was also identified by NBO, GRI, and FMO analyses. This work might be helpful for understanding the significant roles of phosphine catalyst and thus provide valuable insights on the rational design of potential catalysts for this kind of reactions.

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Stereoselective syntheses of α,β-unsaturated γ-amino esters through phosphine-catalyzed γ-umpolung additions of sulfonamides to γ-substituted allenoates

Cited by 21 publications

References 62 publications

Lewis Base-Catalyzed Amino-Acylation of Arylallenes via C–N Bond Cleavage: Reaction Development and Mechanistic Studies

Lewis Base-Catalyzed Amino-Acylation of Arylallenes via C–N Bond Cleavage: Reaction Development and Mechanistic Studies

Phosphine Organocatalysis

Mechanisms of phosphine‐catalyzed [4 + 3] annulation of allenoates with C, N‐cyclic azomethine imines: A DFT investigation

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