Premium
A semiempirical investigation of the mechanisms for the alkylation of arylamines
Author(s) -
Chaka Anne M.
Publication year - 1995
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560530605
Subject(s) - alkylation , chemistry , protonation , electrophile , olefin fiber , computational chemistry , cycloaddition , ring (chemistry) , transition state , aniline , friedel–crafts reaction , molecular orbital , reaction mechanism , catalysis , organic chemistry , molecule , ion
The alkylation of arylamines is an important reaction in many large scale industrial processes. Three possible mechanisms are evaluated at the semiempirical level using the alkylation of aniline with ethylene as a model system. A molecular orbital analysis is performed for each mechanism to determine the appropriate type of wavefunction required to describe the transition state. Successive levels of refinement in search algorithms are used to locate the transition state on a potential surface with up to 60 degrees of freedom. A reasonable mechanism for the AlCl 3 ‐catalyzed Friedel‐Crafts alkylation is shown to be analogous to a Diels‐Alder [4 + 2] concerted cycloaddition after initial β‐elimination of HCl. The Brönsted acid‐catalyzed reaction shown is likely to occur via a mechanism similar to the Ene reaction, rather than initial protonation of the olefin followed by electrophilic addition to a nearby aromatic ring. © 1995 John Wiley & Sons, Inc.