Bridgehead atoms
Bridgehead atoms ( English bridgehead atom ) are in Chemistry - more precisely in the structural formulas of chemical compounds - known atoms in larger molecules , such. B. in bridged bicyclic ring systems. The bridgehead atoms are usually carbon atoms , but there are also compounds with two nitrogen bridgehead atoms, for example diazabicyclooctane ( DABCO ). Also, the Tröger's base containing two nitrogen-bridgehead atoms, which also stereocenters represent that does not invert , since the pyramidal configuration is stable.
Tetrahedrane , C 4 H 4 , contains four bridgehead atoms (carbon atoms)
Adamantane contains four bridgehead carbon atoms, as does Twistan . Camphor and cocaine are natural substances that each contain two carbon bridgehead atoms.
The formation of a double bond in a molecule with the participation of a bridgehead atom is often difficult, ie such cycloalkenes are often unstable. This subject is the subject of Bredt's rule .
Bridgehead carbon atoms are found in
- condensed or fused polycyclic alkanes (simple example: decalin , in which two cyclohexane rings share two carbon atoms)
or in
- bridged bicyclic ring systems (simple example: norbornane ).
Individual evidence
- ↑ Jonathan Clayden, Nick Greeves, Stuart Warren: Organische Chemie , Springer Spectrum, 2013, 2nd edition, pp. 920–921. ISBN 978-3-642-34715-3 .
- ↑ Michael B. Smith: March's advanced organic chemistry , John Wiley & Sons, 7th edition, 2013, p. 129, ISBN 978-0-470-46259-1 .
- ^ Siegfried Hauptmann : Organic Chemistry , 2nd revised edition, VEB Deutscher Verlag für Grundstoffindustrie, Leipzig, 1985, p. 227, ISBN 3-342-00280-8 .
- ↑ K. Peter C. Vollhardt: Organische Chemie , VCH, 1990, pp. 164-165, ISBN 3-527-26912-6 .