An Unprecedented Pd‐Catalyzed Carbonylative Route to Fused Furo[3,4‐<italic>b</italic>]indol‐1‐ones.

Abstract: A novel and efficient catalytic approach to functionalized furo[3,4‐<italic>b</italic>]indol‐1‐ones is reported. It is based on a palladium‐catalyzed sequential process involving an initial cyclization of 2‐(hydroxypropyn‐1‐yl)anilines to form the indole moiety, followed by insertion of carbon monoxide and a second annulation step to build a lactone ring. In a single transformation, two fused heterocycles and three new bonds (C−N, C−C and C−O) are generated. The present methodology gives direct access to structurally complex molecules starting from readily available reagents. [ABSTRACT FROM AUTHOR]