The carbon adjacent to an aromatic ring – the “benzylic” carbon – can participate in several useful and interesting reactions. Today we’ll provide examples and mechanisms for two key examples: benzylic bromination and benzylic oxidation.

The allylic carbon atom is the sp 3 hybridized carbon atom in the allylic group RCH 2-CH=CH 2 that is bonded with the -CH=CH 2 group. For example in propene, the highlighted carbon atom is the allylic carbon atom (CH 3 -CH=CH 2 ).

The functional group of alkyl halides is a carbon-halogen bond, the common halogens being fluorine, chlorine, bromine and iodine. With the exception of iodine, these halogens have electronegativities significantly greater than carbon.

What is allylic bromination and how does it work? Examples and mechanism of allylic and benzylic bromination using NBS, peroxides and heat, with references.

As a result, benzylic and allylic carbocations (where the positively charged carbon is conjugated to one or more non-aromatic double bonds) are significantly more stable than even tertiary alkyl carbocations.