The direct thiocyanation of indoles and pyrrole with ammonium
thiocyanate has been achieved using o-iodoxybenzoic
acid (IBX) under mild and neutral conditions to produce indol-3-yl
and pyrrol-2-yl thiocyanates, respectively, in excellent yields
and with high selectivity. This method is effective even with N-substituted arylamines
for the preparation of aryl thiocyanates.
o-iodoxybenzoic acid - electrophilic
substitution - indoles - aryl thiocyanates - heteroaryl
thiocyanates