New Synthetic Protocols for the Preparation of Unsymmetrical Bisindoles

Abstract

Novel unsymmetrical bisindoles were synthesized by a solvent-free C-C bond-formation reaction under mild conditions. Starting from aziridines or hydroxyl precursors, indoles have been used as C-nucleophiles to form new pharmacologically interesting bisindoles via an electrophilic aromatic substitution pathway in good to excellent yields. [reaction: see text]

β‐cyclodextrin‐capped palladium nanoparticle‐catalyzed ligand‐free Suzuki and Heck couplings in low‐melting β‐cyclodextrin/NMU mixtures

“…To circumvent some of these issues, attempts have been made to develop solvent‐green chemistry . Among them, solvent‐free reactions have been successful for a few transformations . However, in performing most organic reactions, solvents play a critical role in making the reaction homogeneous and allowing molecular interactions to be more efficient.…”

Phenyltrimethylammonium Tribromide: A Versatile Reagent in Organic Synthesis

“…23 The aziridination of the alkene can also be carried out employing an understoichiometric amount of chloramines-T trihydrate in the presence of 5 mol% PTAB. 24 (F) Coupling Reaction of Carbon Dioxide and Epoxides: A combination of SalenRu(PPh 3 ) 2 25 or metal porphyrin 26 with PTAB has been used as novel and high efficient catalysts for the coupling reaction of carbon dioxide and epoxides to yield the corresponding cyclic carbonates. Copyright of Synlett is the property of Georg Thieme Verlag Stuttgart and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission.…”

“…23 The aziridination of the alkene can also be carried out employing an understoichiometric amount of chloramines-T trihydrate in the presence of 5 mol% PTAB. 24 (F) Coupling Reaction of Carbon Dioxide and Epoxides: A combination of SalenRu(PPh 3 ) 2 25 or metal porphyrin 26 with PTAB has been used as novel and high efficient catalysts for the coupling reaction of carbon dioxide and epoxides to yield the corresponding cyclic carbonates.…”

Diastereoselective Nucleophilic Ring‐Opening Reactions of 2,6‐Diazasemibullvalenes for the Synthesis of Diverse Functionalized Δ1‐Bipyrroline Derivatives

“…The regioselectivity is comparable to the C3 alkylation of indole derivatives with normal aziridines, which gives tryptophan derivatives or 3-substituted indoles as products. [16] It was reported that scandium triflate could catalyze ring expansion of activated aziridines with indole derivatives to give pyrrolo [2,3-b]indoles as the [3+2] cycloaddition product. [17] However, the reaction of 1 with N-methylindole under similar conditions did not give the expected [3+2] cycloaddition product 12; instead, only the ring-opened product 11 was isolated.…”