Copper(i) Iodide-Catalyzed Cycloadditions of (1Z,4R*,5R*)-4-Benzamido-5-phenylpyrazolidin-3-on-1-azomethine Imines to Ethyl Propiolate

Lidija Pezdirc; Branko Stanovnik; Jurij Svete

doi:10.1071/CH09074

RESEARCH ARTICLE

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Copper(i) Iodide-Catalyzed Cycloadditions of (1Z,4R,5R)-4-Benzamido-5-phenylpyrazolidin-3-on-1-azomethine Imines to Ethyl Propiolate

Lidija Pezdirc ^A , Branko Stanovnik ^A and Jurij Svete ^A ^B

+ Author Affiliations

- Author Affiliations

^A Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, PO Box 537, 1000 Ljubljana, Slovenia.

^B Corresponding author. Email: jurij.svete@fkkt.uni-lj.si

Australian Journal of Chemistry 62(12) 1661-1666 https://doi.org/10.1071/CH09074
Submitted: 6 February 2009 Accepted: 27 March 2009 Published: 10 December 2009

Abstract

Regioselective copper(i) iodide-catalyzed cycloadditions of chiral pyrazolidin-3-on-1-azomethine imines 3a–j to ethyl propiolate 4 gave cycloadducts 5a–h and 5′i and 5/5′j as single regioisomers. In terms of facial selectivity, cycloadducts 5a–h and 5′i were obtained as single diastereomers, whereas the reaction of dipole 3j was less selective and gave a mixture of 5j and 5′j in a ratio of 15:85. Stereoselectivity of copper(i) iodide-catalyzed cycloadditions of ethyl propiolate 4 to azomethine imines 3 was controlled by the stereodirecting phenyl group at position 5 and by the ortho-substituents at the 1′–Ar residue.

Acknowledgements

Financial support from the Slovenian Research Agency through grants P0–0502–0103, P1–0179, and J1–6689–0103–04 is gratefully acknowledged. We thank pharmaceutical companies Boehringer–Ingelheim Pharma GmbH & Co. KG (Biberach, Germany), Krka d.d. (Novo mesto, Slovenia) and Lek d.d., a new Sandoz company (Ljubljana, Slovenia) for financial support.

References

Copper(i) Iodide-Catalyzed Cycloadditions of (1Z,4R*,5R*)-4-Benzamido-5-phenylpyrazolidin-3-on-1-azomethine Imines to Ethyl Propiolate

Abstract

Acknowledgements

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Copper(i) Iodide-Catalyzed Cycloadditions of (1Z,4R,5R)-4-Benzamido-5-phenylpyrazolidin-3-on-1-azomethine Imines to Ethyl Propiolate