Metal-free stereoselective addition of propiolic acids to ynamides: a concise synthetic route to highly substituted enediyne/dienyne-(E)-N,O-acetals

Prasad, R. Shyam; Kanikarapu, Suresh; Dutta, Shubham; Vangara, Srinivas; Sahoo, Akhila K.

doi:10.1039/d2nj01907h

Cited by 4 publications

(1 citation statement)

References 45 publications

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“…The group of Sahoo prepared useful building block enediynes 52 via the syn -α-addition of propiolic acids with ynamides. 83 With the aid of a gold catalyst, enediynes 52 and water underwent cascade addition and intramolecular cyclization to afford spiro-heterocycles.…”

Section: C–o Bond Formationmentioning

confidence: 99%

Catalytic intermolecular hydrofunctionalizations of ynamides

Zhao,

Jia,

2024

Org. Chem. Front.

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Section: C–o Bond Formationmentioning

confidence: 99%

Catalytic intermolecular hydrofunctionalizations of ynamides

Zhao,

Jia,

2024

Org. Chem. Front.

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HFIP-Mediated, Highly Chemo-, Regio-, and Stereoselective Hydrofunctionalizations of Ynamides: Access to Stereodefined Alkenes Bearing Drugs and Natural Products

Satyanarayana,

Chatterjee

2024

J. Org. Chem.

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We disclose a sustainable and versatile synthetic strategy for the highly chemo-, regio-, and stereoselective hydrofunctionalizations of ynamides, through its activation by a solvent, HFIP, to access a wide variety of stereodefined ketene N,N, N,O, N,S, and N,Se acetals in high yield at room temperature. The reaction proceeded through the formation of the reactive keteniminium ion intermediate, formed via protonation at the β-carbon of ynamide by HFIP, followed by an attack of a nucleophile (syn-addition) at the α-carbon. When ynamides are treated with only HFIP at room temperature, the HFIP addition products of ynamides are formed in a 100% atom-economic fashion; however, in the presence of a stronger N-/O-/S-/Se-based nucleophile, the corresponding syn-hydroheterofunctionalized products are formed. Notably, HFIP played multiple roles, such as a reagent, in particular, a Brønsted acid, nucleophile, as well as solvent. Interestingly, HFIP is found to be unique for this transformation. Notably, this strategy is utilized for the late-stage functionalization of several marketed drugs and natural products, and it also enables the connection of two different drugs or a drug and a natural product through chemical bonds. Significantly, HFIP was recovered after the reaction and reused for consecutive reactions.

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A 6-endo-dig Thiolative Cyclization of Yne-Ynamides: Access to Thiodihydropyridin-2-ones

et al. 2022

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A straightforward regioselective intramolecular 6-endo-dig cyclization of yne-tethered ynamide is herein developed. The reaction involves an intramolecular enolate attack of ketene-N,O-acetals, generated in situ from yne-ynamide and methanesulfonic acid, to the alkyne moiety activated by a sulfonium cation. The transformation enables access to structurally diverse 5-(arylthio)-3,6-dihydropyridin-2(3H)-ones with broad functional group compatibility. The recovery of S-protecting groups and synthetic applications of the products make the transformation useful.

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Metal-free stereoselective addition of propiolic acids to ynamides: a concise synthetic route to highly substituted enediyne/dienyne-(E)-N,O-acetals

Abstract: A straight forward and sustainable approach for 1,2-addition of propiolic acids to ynamide has led to bench stable sp2 (E)-enol-enamides of enediynes & dienynes. The reaction is chemo, regio, as...

Cited by 4 publications

References 45 publications

Catalytic intermolecular hydrofunctionalizations of ynamides

Catalytic intermolecular hydrofunctionalizations of ynamides

HFIP-Mediated, Highly Chemo-, Regio-, and Stereoselective Hydrofunctionalizations of Ynamides: Access to Stereodefined Alkenes Bearing Drugs and Natural Products

A 6-endo-dig Thiolative Cyclization of Yne-Ynamides: Access to Thiodihydropyridin-2-ones

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