Synthetic Approach to Dictyodendrins: A Facile Synthesis of Pyrrolo[2,3‐c]carbazole, Pyrrolodibenzothiophene, and Benzo[e]indole

Abstract

The FeCl3/DDQ‐PTSA/NBS‐mediated cyclization (DDQ = 2,3‐dichoro‐5,6‐dicyano‐1,4‐benzoquinone, PTSA = p‐toluenesulfonic acid, NBS = N‐bromosuccinimide) of 2‐arylvinyl‐3‐indolylpyrrole led to the formation of the pyrrolo[2,3‐c]carbazole core unit of dictyodendrins in yields of 75–90 %. The cyclization method was also successfully applied to the syntheses of pyrrolodibenzothiophene and benzo[e]indole derivatives.

Synthesis and Applications of Dihydropyrrolocarbazoles

“…Cyclization of 2‐vinyl‐3‐(pyrrol‐3‐yl)indole derivatives into pyrrolo[2,3‐ c ]carbazoles could also be mediated by a variety of other conditions, as reported by Raju and Mohanakrishnan . Cyclization of compounds 117a – c in the presence of 0.5 equiv.…”

“…Synthetic approaches to 3,6‐dihydropyrrolo[2,3‐ c ]carbazole derivatives reported by Raju and Mohanakrishnan …”

“…[33] This photochemical electrocyclization/aromatization strategy leading to the formation of cycle B of the 3,6-dihydropyrrolo[2,3-c]carbazole scaffold was also applied by Ayats et al, [34] leading to 115 as a simplified dictyodendrin core, although with 25 [2,3-c]carbazoles could also be mediated by a variety of other conditions, as reported by Raju and Mohanakrishnan. [35] Cyclization of compounds 117a-c in the presence of 0.5 equiv. of FeCl 3 (Cond.…”

“…Synthetic approaches to 3,6-dihydropyrrolo [2,3-c]carbazole derivatives reported by Raju and Mohanakrishnan. [35] Scheme 21. Electrocyclization of 2-ethynyl-3-(pyrrol-3-yl)indole 122 and proposed mechanism for the formation of the minor regioisomer 125.…”

Synthesis and functionalization of 3-bromo-2-(2-chlorovinyl)benzothiophenes as molecular tools

“…6 In a continuation of our work dedicated to the synthesis of functionalized heterocycles, 7 we described a new method to prepare a variety of stereo-dened polyhalogenated platforms 6 through the N-methyl-pyrrolidin-2-one hydrotribromide (MPHT)-promoted bromocyclization of (Z)-and (E)-chloroenynes 5 and subsequent site-selective Suzuki-Miyaura coupling reactions of 6 to prepare various 2,3-disubstituted benzothiophenes 1 (Scheme 2).…”