Iridium-catalyzed [2+2+2] cycloaddition of α,ω-diynes with isocyanates.
J Org Chem. 2012 Jan 20; 77(2):908-20.JO

Abstract

[Ir(cod)Cl](2)/BINAP was found to be an efficient catalyst for the [2+2+2] cycloaddition of α,ω-diynes with isocyanates to give 2-pyridones. A wide range of isocyanates can be used for this reaction. Both aliphatic and aromatic isocyanates smoothly reacted with α,ω-diynes to give 2-pyridones in high yields. Aliphatic isocyanates were more reactive than aromatic isocyanates. For aromatic isocyanates, the electronic properties of the substituents affected the reactivity: electron-donating substituents enhanced the reaction. The reaction of unsymmetrical α,ω-diynes possessing two different internal alkyne moieties with isocyanates was regiospecific and gave a single product. This regioselectivity could be explained by the reaction of iridacyclopentadiene with a nitrogen-carbon double bond. The regioselectivity of the reaction of malonate-derived diyne was controlled by a steric effect, while that of the reaction of ester-tethered diyne was controlled by an electronic effect. [Ir(cod)Cl](2)/chiral diphosphine catalyst could be used for the enantioselective synthesis of C-N axially chiral 2-pyridone. The reaction of diyne 1a with o-methoxyphenyl isocyanate (7a) gave C-N axially chiral 2-pyridone (R)-8aa in 78% yield with 94% ee.

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Authors+Show Affiliations

Onodera G

Department of Chemistry and Biological Science, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258, Japan.

Suto M

No affiliation info available

Takeuchi R

No affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

22142026

Citation

Onodera, Gen, et al. "Iridium-catalyzed [2+2+2] Cycloaddition of Α,ω-diynes With Isocyanates." The Journal of Organic Chemistry, vol. 77, no. 2, 2012, pp. 908-20.

Onodera G, Suto M, Takeuchi R. Iridium-catalyzed [2+2+2] cycloaddition of α,ω-diynes with isocyanates. J Org Chem. 2012;77(2):908-20.

Onodera, G., Suto, M., & Takeuchi, R. (2012). Iridium-catalyzed [2+2+2] cycloaddition of α,ω-diynes with isocyanates. The Journal of Organic Chemistry, 77(2), 908-20. https://doi.org/10.1021/jo202083z

Onodera G, Suto M, Takeuchi R. Iridium-catalyzed [2+2+2] Cycloaddition of Α,ω-diynes With Isocyanates. J Org Chem. 2012 Jan 20;77(2):908-20. PubMed PMID: 22142026.

* Article titles in AMA citation format should be in sentence-case

TY - JOUR T1 - Iridium-catalyzed [2+2+2] cycloaddition of α,ω-diynes with isocyanates. AU - Onodera,Gen, AU - Suto,Mari, AU - Takeuchi,Ryo, Y1 - 2011/12/23/ PY - 2011/12/7/entrez PY - 2011/12/7/pubmed PY - 2011/12/7/medline SP - 908 EP - 20 JF - The Journal of organic chemistry JO - J Org Chem VL - 77 IS - 2 N2 - [Ir(cod)Cl](2)/BINAP was found to be an efficient catalyst for the [2+2+2] cycloaddition of α,ω-diynes with isocyanates to give 2-pyridones. A wide range of isocyanates can be used for this reaction. Both aliphatic and aromatic isocyanates smoothly reacted with α,ω-diynes to give 2-pyridones in high yields. Aliphatic isocyanates were more reactive than aromatic isocyanates. For aromatic isocyanates, the electronic properties of the substituents affected the reactivity: electron-donating substituents enhanced the reaction. The reaction of unsymmetrical α,ω-diynes possessing two different internal alkyne moieties with isocyanates was regiospecific and gave a single product. This regioselectivity could be explained by the reaction of iridacyclopentadiene with a nitrogen-carbon double bond. The regioselectivity of the reaction of malonate-derived diyne was controlled by a steric effect, while that of the reaction of ester-tethered diyne was controlled by an electronic effect. [Ir(cod)Cl](2)/chiral diphosphine catalyst could be used for the enantioselective synthesis of C-N axially chiral 2-pyridone. The reaction of diyne 1a with o-methoxyphenyl isocyanate (7a) gave C-N axially chiral 2-pyridone (R)-8aa in 78% yield with 94% ee. SN - 1520-6904 UR - https://www.unboundmedicine.com/medline/citation/22142026/Iridium_catalyzed_[2+2+2]_cycloaddition_of_αω_diynes_with_isocyanates_ L2 - https://doi.org/10.1021/jo202083z DB - PRIME DP - Unbound Medicine ER -

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Iridium-catalyzed [2+2+2] cycloaddition of α,ω-diynes with isocyanates.J Org Chem. 2012 Jan 20; 77(2):908-20.JO