A simple and efficient method for the thiocyanation of indoles and
phenols has been developed. In this protocol, the substrates are converted
into 3-thiocyanatoindoles and 4-thiocyanatophenols, respectively,
by treatment with equimolar amounts of C2Cl6 and KSCN in
DMSO at 120°C in the presence of a catalytic amount of CuI. The
reaction proceeds smoothly under ligand- and additive-free conditions
to afford the desired products in good to excellent yields.
Control experiments confirmed that both CuI and C2Cl6 are essential
for the transformation, as no product formation occurs in their
absence. Moreover, DMF was also found to be a suitable solvent for
this transformation.