Phosphine-catalyzed [4+2] annulations of α-aminonitriles with allenoates: Synthesis of functionalized tetrahydropyridines

Jang, Ho‐Chol; Liu, Wei; Sean, Xiao’an Zhang; Liao, Wei‐Wei

doi:10.1007/s40242-016-5495-x

Cited by 8 publications

(4 citation statements)

References 38 publications

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“…In 2016, Liao and co-workers developed a phosphine-catalyzed [4 + 2] annulation of α -aminonitriles with allenoates for the synthesis of diversely substituted tetrahydropyridines bearing quaternary carbon centers (Scheme 169). 233 In this reaction, α -aminonitriles function as C,N -bisnucleophilic reaction partners while 2-(acetoxymethyl) buta-2,3-dienoates operate as C4 synthons. In the presence of PPh 3 (20 mol %) and Cs 2 CO 3 (130 mol %), α -aminonitriles featuring various N -aryl (R 1 ) groups and R 2 groups were suitable substrates for the reaction, providing their [4 + 2] annulation products in moderate to high yields.…”

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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Section: Nucleophilic Phosphine Catalysis Of Allenesmentioning

confidence: 99%

Phosphine Organocatalysis

et al. 2018

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“…In 2016, α-aminonitriles 124 were employed as C , N -bisnucleophiles to react with 2-(acetoxymethyl)buta-2,3-dienoates by Liao, Zhang and coworkers ( Scheme 36 ) [ 75 ]. Under the catalysis of PPh 3 , the [4+2] cycloaddition of a wide range of α-aminonitriles 124 proceeded smoothly to furnish the corresponding poly-substituted tetrahydropyridines 125 which include a quaternary carbon stereocenter in moderate to good yields.…”

Section: [4+x] Annulations Of β′-Acetoxy Allenoatesmentioning

confidence: 99%

“… Phosphine-catalyzed [4+2] annulations of α-aminonitriles with 2-(acetoxymethyl)buta-2,3-dienoate [ 75 ]. …”

Section: Schemesmentioning

confidence: 99%

Organophosphine-Catalyzed [4C+X] Annulations

Chen

et al. 2018

Molecules

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In recent years, there have been extraordinary developments of organophosphine-catalyzed reactions. This includes progress in the area of [4C+X] annulations, which are of particular interest due to their potential for the rapid construction of 5–8-membered cyclic products. In this short overview, we summarize the remarkable progress, emphasizing reaction mechanisms and key intermediates involved in the processes. The discussion is classified according to the type of electrophilic reactants that acted as C4 synthons in the annulation process, in the order of α-alkyl allenoates, γ-alkyl allenoates, α-methyl allene ketones, β′-OAc allenoate, δ-OAc allenoate, activated dienes and cyclobutenones.

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“…Later, Fu and coworkers found the chiral spirophosphine catalyst can obviously improve the enantioselectivity of [4 + 1] annulation [8] of allenoate and amine (Scheme 1B). Subsequently, Liao group provided a [4 + 2] annulation [9] between allenoate and secondary amine (Scheme 1C). In the three reactions mentioned above, allenes act as C4 synthons, which is remarkably different from the phosphine-catalyzed [3 + 2] annulation between allenes and unsaturated imine.…”

Section: Introductionmentioning

confidence: 99%

Possible Mechanisms and Origin of Selectivities for Phosphine‐Catalyzed [2+n] (n=3, 4) Annulations of Saturated Amines and δ‐Acetoxy Allenoates

Yang

Wang

et al. 2021

Asian J Org Chem

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The density functional theory (DFT) calculations were performed to gain insights into possible reaction mechanisms and origin of selectivities on phosphine catalyzed [2+3] and [2+4] annulations of saturated amine with allenoate for the first time. The computed results reveal that allenoate prefers to serve as a C3 synthon rather than C4 synthon under phosphine catalysis, and the whole catalytic cycle generally undergoes through eight processes, i. e. (1) adsorption of catalyst, (2) dissociation of AcO− group, (3) deprotonation of saturated amine, (4) nucleophilic attack by the deprotonated amine anion to the electrophilic phosphonium diene intermediate, (5) [1,6]‐proton shift, (6) ring closure of five‐membered heterocycle, (7) [1,2]‐proton shift, and (8) desorption of catalyst and the formation of 3‐pyrroline. The fourth step was identified as both chemo‐ and stereo‐selectivities determining step, and the pathway associated with R‐isomer is energetically favorable pathway. Further non‐covalent interaction (NCI) and Bader's atoms‐in‐molecules (AIM) analysis reveal that the C−H⋅⋅⋅O interaction has a significant contribution to the stability of R‐configured transition state. The obtained insights should be valuable for understanding the general principle for the detailed mechanism and predicting the origin of the chemo‐ and stereo‐selectivities on the phosphine catalyzed [2+3] and [2+4] annulations of saturated amine with allenoate.

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Phosphine-catalyzed [4+2] annulations of α-aminonitriles with allenoates: Synthesis of functionalized tetrahydropyridines

Cited by 8 publications

References 38 publications

Phosphine Organocatalysis

Phosphine Organocatalysis

Organophosphine-Catalyzed [4C+X] Annulations

Possible Mechanisms and Origin of Selectivities for Phosphine‐Catalyzed [2+n] (n=3, 4) Annulations of Saturated Amines and δ‐Acetoxy Allenoates

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