A Comprehensive Overview of the Synthesis of Tetrahydrocarbazoles and its Biological Properties

Tetrahydrocarbazoles (THC) is a privileged structural scaffold containing natural indole as the central moiety. This extraordinary skeleton features in a plethora of naturally occurring pharmacological compounds and alkaloids exhibiting a significant inhibitory activity such as antibacterial, protein kinase inhibitor, and tumor growth inhibitor, etc. Due to its versatile biological properties, it always gains considerable attention among the scientific community. The main objective of this review is to make a comprehensive reference work on the synthesis and biological properties of THCs, thus targeting a broad audience on the assessment of various catalysts along with their reaction condition, mechanism of action, and yield, which are categorized into three groups: 1) organocatalyzed reactions; 2) TfOH catalyzed reactions; 3) metal-catalyzed reactions and 4) miscellaneous.