The Pschorr Synthesis and Related Diazonium Ring Closure Reactions
Published Online: 15 MAR 2011
Copyright © 2004 by Organic Reactions, Inc. Published by John Wiley & Sons, Inc.
How to Cite
DeTar, D. F. 2011. The Pschorr Synthesis and Related Diazonium Ring Closure Reactions. Organic Reactions. 9:7:409–462.
- Published Online: 15 MAR 2011
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In the middle 1890s, three groups of chemists independently discovered a new cyclization reaction of certain appropriately constituted diazonium salts. Fischer and Schmidt reported that an aqueous solution of 2-benzylbenzenediazonium chloride furnished fluorene on heating. Graebe and Ullman reported that 2-benzoylbenzenediazonium chloride yielded fluorenone and Staedel reported a somewhat similar result from the action of nitrous acid on 2,2'-diaminbenozpehnone, a reaction that produced a little 1-hydroxyfluorenone. Two years later, Robert Pschorr applied the ring closure reaction to the diazonium salt derived from trans-2-amino-alpha-phenylcinnamic acid to obtain phenanthrene-9-carboxylic acid. The principal utility of these cyclizations reactions has been the synthesis of substituted ring structures in which the positions of the substituents are known.
- Pschorr synthesis;
- diazonium ring closures. Bridge;
- side reactions;
- simultaneous ring closures;
- aliphatic analogs;
- Gomberg-Bachmann synthesis