Bischler-Napieralski reaction in total synthesis of isoquinoline-based natural products. An old reaction, a new application

Bischler-Napieralski (B-N) reaction is undoubtedly one of the most powerful methodologies in organic synthesis for the construction of isoquinoline moieties as important heterocyclic compounds. It has also captured great attention in the total synthesis of naturally occurring compounds such as alkaloids, which mostly and particularly bear isoquinolines as scaffold in their structures. The present review is focused on and highlighted the applications of B-N reaction, a rather old reaction, as a decisive and important stage in the total synthesis of some naturally occurring compounds including alkaloids showing significant biological activities.