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Azomethine Imines in Four‐ and Five‐Membered Rings: Stable Cyclic Valence Isomers of an α ‐(Phenyldiazenyl)ketocarbene
Author(s) -
Schantl Joachim G.,
Rettenbacher Arno S.,
Wurst Klaus
Publication year - 1998
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/(sici)1521-3773(19980904)37:16<2229::aid-anie2229>3.0.co;2-#
Subject(s) - isomerization , valence (chemistry) , chemistry , rhodium , sydnone , stereochemistry , ring (chemistry) , medicinal chemistry , catalysis , organic chemistry
The expected Wolff rearrangement of the ketocarbene intermediate 2 , formed upon rhodium( II )‐catalyzed elimination of nitrogen from diazoketone 1 , does not occur. Instead, by incorporation of the neighboring diazene group the surprisingly stable, crystalline azomethine imines 3 and 4 are formed as cyclic valence isomers of 2 . Compound 4 , which contains a five‐membered ring, is the first representative of a carba‐sydnone and can also be obtained by acid‐catalyzed isomerization of 3 at 50–70°C.