Metal-Free Regioselective Hypervalent Iodine-Mediated C-2 and C-3 Difunctionalization of N-Substituted Indoles

Mild, metal-free, highly regioselective hypervalent-iodine mediated C-2 acetoxylation and C-3 oxidations of N -substituted indoles with (diacetoxyiodo)benzene [PhI(OAc) 2 ] have been reported. The reaction involves three cascade steps. The quantity of PhI(OAc) 2 employed in this reaction plays a key role in the outcome of three types of products ( 2a – 4a ). Furthermore, the mild and highly regioselective C-2 oxidation and C-3 dichlorination of N -substituted indoles with PhICl 2 have been developed. Extensive studies including in situ IR techniques and H 2 O 18 -labeling experiment were performed to gain insight into the possible reaction mechanism.