Synthesis of chiral 3-substituted hexahydropyrroloindoline via intermolecular cyclopropanation

A new and efficient synthetic route to chiral 3- substituted hexahydropyrroloindoline 18 possessing absolute configurations in accordance with indole alkaloids has been developed from readily available L- tryptophan. The key step relies on the one- pot cascade reaction of oxazolidinone 17 with diazoester, which proceeds through intermolecular cyclopropanation, ring opening, and cyclization.