140 years ago Adolf von Baeyer proposed the structure of a heteroaromatic compound which revolutionized organic and medical chemistry: indole. After more than a century, indole itself and the complexity of naturally occurring indole derivatives continue to inspire and influence developments in synthetic chemistry. In particular, the ubiquitous presence of indole rings in pharmaceuticals, agrochemicals, and functional materials are testament to the ever increasing interest in the design of mild and efficient synthetic routes to functionalized indole derivatives. This Review emphasizes the achievements in the selective catalytic functionalization of indoles (C-C bond-forming processes) over the last four years.

Catalytic Functionalization of Indoles in a New Dimension

A review on recent developments of indole-containing antiviral agents.

Simple indole alkaloids and those with a nonrearranged monoterpenoid unit

Vor 140 Jahren schlug Adolf von Baeyer die Struktur fur eine heteroaromatische Verbindung vor, die die organische und medizinische Chemie nachhaltig veranderte: Indol. Nach mehr als einem Jahrhundert beeinflussen Indol selbst, ebenso wie naturliche Indolderivate, weitgehend die Entwicklung in der Synthesechemie. Vor allem die allgegenwartige Prasenz des Indolrings in pharmazeutischen und agrochemischen Verbindungen sowie seine Verwendung in der Materialchemie sind ausschlaggebend fur das anhaltende Interesse an der Entwicklung von neuen milden und effizienten Synthesestrategien fur funktionalisierte Indolderivate. Dieser Aufsatz fasst die Fortschritte hinsichtlich der selektiven katalytischen Funktionalisierung von Indolen (durch C-C-Kupplung) aus den vergangenen vier Jahre zusammen.

Katalytische Funktionalisierung von Indolen in einer neuen Dimension

A cationic iridium-catalyzed C2-alkylation of N-substituted indole derivatives with various alkenes has been developed, which selectively gives linear or branched 2-alkylindoles in high to excellent selectivity. This protocol relies on the use of the carbonyl group on the nitrogen atom of indole as a directing group: a linear product was predominant when an acetyl group was used as a directing group, and a branched product was predominant with a benzoyl group.

Ir(I)-catalyzed C-H bond alkylation of C2-position of indole with alkenes: selective synthesis of linear or branched 2-alkylindoles.

Reserpine: A Challenge for Total Synthesis of Natural Products

Practical and Phase Transfer–Catalyzed Synthesis of 6‐Methoxytryptamine

A convenient and cost‐effective synthesis of 6‐methoxytryptamine (1), starting from commercially available phthalimide and 1‐bromo‐3‐chloropropane via PTC N‐alkylation, PTC C‐alkylation, Japp–Klingemann reaction, hydrolysis, and decarboxylation, has been accomplished with a 44% overall yield.

Jian Huang

Papers

Reserpine: A Challenge for Total Synthesis of Natural Products

Practical and Phase Transfer–Catalyzed Synthesis of 6‐Methoxytryptamine

Reserpine: A Challenge for Total Synthesis of Natural Products

Practical and Phase Transfer Catalyzed Synthesis of 6‐Methoxytryptamine.