AcOH-mediated dichloroimination of indoles using chloramine-B: a facile access to 2,3-functionalized indolines

Abstract

A new and mild method for the efficient synthesis of 3,3-dichloro-2-sulfonyliminoindolines via AcOH-mediated dichloroimination of indoles using chloramine-B is presented. Application of this method to the efficient construction of pyrrolidinoindoles and N-C3 linked pyrrolidinoindolines is demonstrated.

Titania‐Supported Gold Nanoparticles as Efficient Catalysts for the Oxidation of Cellobiose to Organic Acids in Aqueous Medium

“…Upon subjecting indole 1z or tert ‐butyl 1 H ‐indole‐1‐carboxylate ( 1aa ) to the optimized conditions, oxidation was not observed (Scheme , a, b). Interestingly, the optimized method worked with 1,3‐dimethyl‐1 H ‐indole ( 1bb ), which provided unexpected product 7D in 71 % yield (Scheme , c); this product was also obtained through the AcOH/chloramine‐B‐mediated dichloroimination of indoles previously developed in our group 19…”

“…However, to the best of our knowledge, these transformations have never been investigated with indoles, and the direct oxidation of indoles through an I 2 ‐catalyzed transformation by using a chloramine salt has not been reported. Recently, our group described the efficient synthesis of 2,3‐functionalized indolines through AcOH‐mediated dichloroimination of indoles by using chloramine‐B,19 which prompted us to explore the possibility of the direct oxidation of indoles by using the I 2 /chloramine‐B system. Herein, we would like to report a practical protocol for the synthesis of isatins through I 2 ‐catalyzed direct oxidation of N ‐substituted indoles by using chloramine‐B as the oxidizing reagent.…”

Electrochemical Iodoamination of Indoles Using Unactivated Amines

“…Recently, Yu, Tan, and co-workers developed the chloroamidation of indoles with sulfonamides and NaClO under metal-free conditions . The concomitant introduction of a halogen and of a nitrogen functional group on indole derivatives has also been developed or observed with other strategies . Despite the considerable progress that has been made in this field, the existing protocols usually require stoichiometric quantities of oxidant, hypervalent iodines­(III), or transition metals (Cu and Pd), all with limited functional group tolerance (Scheme a).…”

Accessing the HMF Derivatives from Furfural Acetate through Oxidative Carbonylation

“…It is worth mentioning that only a small amount of the carbonylation product were detected when using either Cu(OAc) 2 or O 2 alone as the oxidant source, suggesting that both oxygen and Cu(II) are essential for efficient re-oxidation of the Pd 0 in the catalytic cycle (Table 1, entries 16 and 17). [17] Next, the influence of different solvents on carbonylation was investigated. The yield decreased dramatically when toluene was employed as the sole solvent ( Apparently, due to the robust CÀH bond of the furan frame, oxidative carbonylation of furfuryl acetate by Pd(OAc) 2 catalyst is very sluggish under current conditions.…”

“…[12] A simplified mechanism was proposed for this oxidative carbonylation reaction as shown in Scheme 1 which is similar to those in the literature. [17,20,21] At first, the C À H activation of furfuryl acetate at 5-position by Pd(OAc) 2 In summary, we have explored a novel route for furfural based resource utilization through oxidative carbonylation to HMF derivatives. Although the current catalyst system is complicated, and the yield is also modest, the continuous endeavors on this process may provide a promising route for furfural based resource utilizations.…”