Highly diastereoselective samarium diiodide induced cyclizations of new 3-substituted indole derivatives

Herein, we describe the synthesis of new functionalized tricyclic and tetracyclic indole derivatives via samarium diiodide induced ketyl cyclizations. The intermediate samarium organyls were either protonated using different proton sources or alkylated with various electrophiles in a highly diastereoselective manner. The obtained products were subjected to further transformations leading to synthetically interesting building blocks.