Properties and Reactions of Indoles, Isoindoles, and Their Hydrogenated Derivatives

Carbon Nucleophilicities of Indoles in SNAr Substitutions of Superelectrophilic 7-Chloro-4,6-dinitrobenzofuroxan and -benzofurazan

“…Besides the synthesis and characterization of the resulting products, a detailed kinetic investigation of the great majority of the C−C couplings studied has been carried out. The results obtained extend considerably the domain of reactivity of indoles as carbon nucleophiles, , allowing a ranking of the electrophilicity of neutral DNBF-Cl and DNBZ-Cl substrates on the comprehensive electrophilicity scale E defined for cationic electrophiles by Mayr et al Although this result was perhaps to be expected, it is the first time that the reactivity of S N Ar substrates is found to be suitably described by this general linear free energy relationship. A preliminary communication of this work dealing only with 3g , 9 , and 14 has appeared …”

One-pot conversion of aromatic compounds to the corresponding bis(indolyl)methanes by the Vilsmeier–Haack reaction

“…Synthetically the reaction of 1H-indole with aldehydes or ketones produces azafulvenium salts that react further with a second 1H-indole molecule to form bis(indol-3yl)methanes [6]. In recent years, synthesis routes to this class of molecules under mild conditions have been reported, with promoters such as montmorillonite clay K-10 [7], trichloro-1,3,5-triazine [8], AlPW 12 O 40 [9], sodium dodecyl sulfate (SDS) [10], ZrCl 4 [11], H 2 NSO 3 H [12], I 2 [4], zeolites [13], bentonite [14], In(OTf) 3 /ionic liquid [15], CuBr 2 [16], Dy(OTf) 3 /ionic liquid [17], HClO 4 -SiO 2 [18], InCl 3 [19], MW/Lewis acids (FeCl 3 , BiCl 3 , InCl 3 , ZnCl 2 , CoCl 2 ) [20], NaHSO 4 and Amberlyst-15 [21], sulfated zirconia [22], ZrOCl 2 /SiO 2 [23], silica sulfuric acid (SSA) [24], TiO 2 [25], (NH 4 ) 2 HPO 4 [26], acidic ionic liquid [27], NaBF 4 [28], metal hydrogen sulfates [29], tetrabutylammonium tribromide [30], superacid SO 4 2À /TiO 2 [31], NaHSO 4 / ionic liquid [32], NBS [33], Ph 3 CCl [34], H 3 PW 12 O 40 [35], LiClO 4 [36], Zr(DS) 4 [37], and Bi(NO 3 ) 3 .5H 2 O [38].…”