Ring-Opening Cyclization (ROC) of Aziridines with Propargyl Alcohols: Synthesis of 3,4-Dihydro-2H-1,4-oxazines

Bharat Singh, Manish Kumar, Gaurav Goswami, Indresh Verma and Manas K. Ghorai*

*Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India, Email: mkghoraiiitk.ac.in

B. Singh, M. Kumar, G. Goswami, I. Verma, M. K. Ghorai, J. Org. Chem., 2023, 88, 4504-4518.

DOI: 10.1021/acs.joc.2c03093

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Abstract

Aziridines react with propargyl alcohols in the presence of Zn(OTf)₂ as the Lewis acid catalyst, following an S_N2-type ring-opening mechanism to furnish the corresponding amino ether derivatives. In the presence of Zn(OTf)₂ and tetrabutylammonium triflate salt, those amino ethers further undergo intramolecular hydroamination via 6-exo-dig cyclization to provide 3,4-dihydro-2H-1,4-oxazine products.

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proposed mechanism

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Key Words

3,4-Dihydro-2H-1,4-oxazines, S_N2-type ring-opening, Ring-opening cyclization (ROC)

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ID: J42-Y2023