An Experimental and Computational Assessment of Acid-Catalyzed Azide-Nitrile Cycloadditions
David Cantillo, Bernhard Gutmann and C. Oliver Kappe *
*Christian Doppler Laboratory for Microwave Chemistry (CDLMC) and Institute of Chemistry, Karl-Franzens-University Graz, Heinrichstrasse 28, A-8010 Graz, Austria, Email: oliver.kappeuni-graz.at
D. Cantillo, B. Gutmann, C. O. Kappe, J. Org. Chem., 2012, 77, 10882-10890.
DOI: 10.1021/jo3022742
Abstract
Activation of the nitrile substrate by the Brønsted or Lewis acid catalyst is responsible for rate enhancement in azide-nitrile cycloaddition. Lewis acids such as Zn or Al salts perform in a similar manner, activating the nitrile moiety and leading to an open-chain intermediate that subsequently cyclizes to produce the tetrazole nucleus. The desired tetrazole structures were obtained in high yields within 3-10 min employing controlled microwave heating.
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D. Cantillo, B. Gutmann, C. O. Kappe, J. Am. Chem. Soc., 2011, 133, 4465-4475.
Key Words
Tetrazoles, Microwave Synthesis
ID: J42-Y2012-3760