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Regioselective Synthesis of Alkylarenes by Two‐Step ipso ‐Substitution of Aromatic Dicarboxylic Acids
Author(s) -
Bramborg Andrea,
Linker Torsten
Publication year - 2012
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201200823
Subject(s) - chemistry , alkylation , regioselectivity , electrophilic aromatic substitution , naphthalene , dicarboxylic acid , organic chemistry , terephthalic acid , carboxylation , medicinal chemistry , catalysis , polyester
A strategy for the regioselective alkylation of arenes was developed, starting from commercially available and inexpensive terephthalic acid or naphthalene‐1,4‐dicarboxylic acid. The method entails a formal ipso ‐substitution of the carboxylate groups by a sequence of reductive alkylation under Birch conditions and subsequent acid‐mediated rearomatization with loss of carbon monoxide and carbon dioxide. More than 20 different arenes with various side‐chains were synthesized. With naphthalene‐1,4‐dicarboxylic acid as starting material, we were able to control the degree of alkylation by choosing the appropriate electrophile in the Birch reduction. Thus, bisalkylated naphthalenes and naphthoic acids became available chemoselectively. All reactions afforded a single regioisomer exclusively in high yields. Overall, aromatic dicarboxylic acids are suitable substrates for a two‐step ipso ‐substitution that allows the selective synthesis of alkylated benzenes and naphthalenes.