Baddeley isomerization
The Baddeley isomerization is a name reaction in organic chemistry . During the reaction there is a rearrangement of the alkyl groups in polyalkylbenzenes . A mixture of a protic acid and a Lewis acid serves as the catalyst .
The reaction was named after George Baddeley, who first reported this rearrangement around 1930.
Overview reaction
In the case of the polyalkylbenzene 1,3,4-tripropylbenzene, a propyl group is rearranged . 1,3,5-tripropylbenzene is obtained as the product.
Reaction mechanism
The mechanism is described in the literature and exemplified using the reaction of 1,4-diethylbenzene to form 1,3-diethylbenzene. In this example, hydrochloric acid was selected as the protonic acid and aluminum chloride as the Lewis acid . It is assumed that the presence of a protic acid and a Lewis acid leads to a direct [1,2] rearrangement:
Cation 2 is formed by the addition of the proton of hydrochloric acid to 1,4-diethylbenzene 1 . In the next two steps, the ethyl group is rearranged and the carbenium ion 3 is formed as an intermediate . The deprotonation in the last step gives the product 1,3-diethylbenzene 4 .
Individual evidence
- ↑ a b c Zerong Wang: Comprehensive Organic Name Reactions and Reagents , Wiley, 2010, ISBN 9780470638859 , pp. 128-131, doi: 10.1002 / 9780470638859 .
- ^ G. Baddeley and GM Bennett: The influence of the sulfur atom on the reactivity of adjacent atoms or groups. Part VI. Aromatic side-chain and nuclear reactivity In: Journal of the Chemical Society , 1933, p. 261, doi: 10.1039 / JR9330000261 .