Allyl position
| ( Blue arrow points to the allyl position) |
|---|
 Propene |
 1-pentene |
 3,3-dimethylcyclohexene |
 3,3,6-trimethylcyclohexene |
As allyl , also allyl , is referred to in the organic chemical to a carbon atom in an unsaturated molecule with a specific chemical reactivity. At least one hydrogen atom is bonded to the carbon atom in question in the allyl position, and at the same time this carbon atom is directly adjacent to a C = C double bond. This hydrogen atom is easily substitutable, e.g. B. by a bromine atom in the radical bromination of alkenes with NBS . This reaction is known as the Wohl-Ziegler reaction . Gross reaction using the example of cyclohexene :
The reaction can be initiated either with the help of a radical initiator or by UV radiation . When selenium dioxide acts on alkenes, these are selectively oxidized in the allyl position to form the corresponding alcohols . The Treibs reaction is another example of a reaction of an alkene that takes place in the allyl position.
Benzyl position
The particular reactivity in a benzyl position is similar to that in the allyl position, a well-known example is the SSS rule .
See also
Individual evidence
- ↑ Reinhard Brückner: reaction mechanisms . 3rd edition, Spektrum Akademischer Verlag, Munich 2004, ISBN 3-8274-1579-9 , p. 218.
- ↑ Michael B. Smith: March's advanced organic chemistry . John Wiley & Sons, 7th Edition, 2013, ISBN 978-0-470-46259-1 , pp. 1470-1471.