Direct intramolecular amination of tryptophan esters to prepare pyrrolo[2,3-b]indoles

CuI-Catalyzed Dearomatization/Peroxidation/Cyclization Cascade of Pyrrole-Tethered Indoles

A mild CuI-catalyzed dearomatization/peroxidation/cyclization cascade of pyrrole-tethered indoles has been reached, providing peroxide-incorporated indolizino[8,7-b]indole derivatives in acceptable to good yields (46-76%). Dehydrogenated peroxide can be obtained by the use of a FeCl3/TBHP (tBuOOH)/2,2,2-trifluoroethanol (TFE) system at 50 °C.

Iodine-Catalyzed Aerobic Diazenylation-Amination of Indole Derivatives

A mild strategy for consecutive diazenylation and amination of indole moieties has been demonstrated. The functionalization occurs at C3 and C2 carbon atoms, respectively, at the indole scaffold in the presence of catalytic iodine and air at 40 °C in the 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) solvent. It is noteworthy that the aromatic amines are generated in situ by the reaction of aryl hydrazine with iodine. In general, bright red products are obtained in moderate to good yield. Control reactions are conducted to establish the reaction mechanism.

Exploration of a KI-catalyzed oxidation system for direct construction of bispyrrolidino[2,3-b]indolines and the total synthesis of (+)-WIN 64821

A facile and environmentally benign KI(cat.)/NaBO₃·4H₂O oxidation system has been developed for the tandem oxidative aminocyclization/coupling of tryptamines, affording a series of 3a,3a′-bispyrrolidino[2,3-b]indolines with high efficiency (up to 94% yield).