ChemInform Abstract: An Easy Access to Carbazolones and 2,3‐Disubstituted Indoles.

Abstract

Different fused pyrrole derivatives are efficiently synthesized by the present new cheap method.

Synthesis of Tetrahydrocarbazol-4-ones via Rh(III)-Catalyzed C–H Activation/Annulation of Arylhydrazines with Iodonium Ylides

“…4 A number of reliable methods for the preparation of tetrahydrocarbazol-4-one derivatives have been developed. Traditionally, tetrahydrocarbazol-4-ones have been synthesized via the intramolecular and intermolecular reactions (Scheme 1), such as classic Fischer indole synthesis (Scheme 1, type a), 5 Heck-type coupling reactions (Scheme 1, type b), 6 oxidative cyclization (Scheme 1, type c), 7 acid-catalyzed cyclization (Scheme 1, type d), 8 reductive cyclization (Scheme 1, type e), 9 and oxidation of 2,3,4,9-tetrahydro-1H-carbazole (Scheme 1, type f). 10 However, these routes often suffer from harsh reaction conditions with high temperatures or strong acids, multistep synthesis, expensive starting materials, or limited substrate scope.…”

Rh-Catalyzed α-Arylation of Cyclic 1,3-Dicarbonyls with Benzocyclobutenols Enabled by a Cyclic Iodonium Ylide Strategy

“…In contrast to the α-arylation of acyclic 1,3-dicarbonyls, achieving Pd-or Cu-catalyzed cross-coupling reactions of cyclic 1,3-dicarbonyls with (pseudo)halides, particularly orthosubstituted ones, remains a significant challenge due to the sluggish reductive elimination resulting from highly stabilized enolates 3 (Scheme 1B, strategy 1). Given these limitations, constructing these structures commonly depends on alternative strategies, such as multistep de novo synthesis, 4 S N Ar of preactivated aryl halides under harsh conditions, 5 or Pinhey arylation 6 that requires the use of stoichiometric toxic reagents (Scheme 1B, strategy 2). To solve these problems, Ball and coworkers recently designed a sulfone-bridged bismacycle to achieve a general α-arylation of cyclic 1,3-dicarbonyls with ortho-substituted boronic acids (Scheme 1B, strategy 3).…”