Chapter 15: Alcohols, Diols and Thiols
Preparation of Thiols
Reaction type: Nucleophilic substitution (SN2)
Summary
A convienient source of
S
is thiourea.
Reaction of the
S
system as a nucleophile with an alkyl halide,
R-X
, in an
SN2 fashion
gives an intermediate
isothiouronium salt
.
Hydrolysis of the intermediate provides the thiol,
R-
S
H
.
These steps can be carried out without isolating the intermediate.
Overall, this is equivalent to treating the alkyl halide,
R-X
, with H
2
S or HS
-
(note: H
2
S is a toxic gas with a very strong odour).
