Iron-Catalyzed Synthesis of Oxindoles: Application to the Preparation of Pyrroloindolines

A novel and highly efficient synthetic approach to pyrroloindolines has been developed. The process is based on tandem radical addition/cyclization with inexpensive iron catalyst. This method tolerates a wide range of N-methyl-N-arylacrylamides as well carbamoyl radicals, providing access to a variety of functionalized 3,3-disubstituted oxindoles, key intermediates for many bioactive pyrroloindolines such as (±)-esermethole, (±)-deoxyeseroline, and (±)-physovenol methyl ether.