Abstract
Kinetics studies for the coupling reactions of the 3-X-thiophene
1a-c
(X = CH
3
, H and Br) with the electrophiles
2a
and
3a-c
have been investigated in acetonitrile at 20°C The second-order rate constants have been employed to determine the nucleophilicity parameters N and s of the thiophene
1
according the Mayr equation log
k
(20°C) = s (E + N). The nucleophilic-specific parameters N and s quantified in this work have been derived and compared with the reactivity of other C nucleophiles. Based on the linear correlations log
k
1
=
f
(E) and log
k
1
=
f
(
σ
p
+
), we have shown that the mechanism of interactions occurs by a unique process: electrophilic heteroaromatic substitution of an
α
-carbon position of substituted 3-X-thiophenes
1
known hyperortho correlation.