Total Synthesis of Hapalindole Alkaloids via Cascade Prins-type Cyclization

Abstract

This brief highlight described about our recently reported method of cascade Prins-type cyclization method. Structural complexity and interesting biological activity made hapalindole alkaloid an attractive choice to the synthetic organic chemist over the past few decades. Keeping the importance of hapalindole scaffolds in mind, in this line, we recently disclosed a redox-neutral, biomimetic Prins-type cyclization between indole and an aldehyde bearing a terminal ene-promoter. The mild reaction protocol allows incorporation of several key functionalities in the products, and products were isolated with excellent yields and diastereoselectivities. Applying this strategy total synthesis of seven hapalindole alkaloids and formal synthesis of two more related alkaloids were accomplished in a stereodivergent manner in relatively fewer synthetic steps.