Iron-Catalyzed Ring Expansion of Cyclobutanols for the Synthesis of 1-Pyrrolines by Using MsONH3OTf.

The synthesis of 1-pyrrolines from cyclobutanol derivatives and an aminating reagent (MsONH3OTf) has been developed. This one-pot procedure achieves C-N bond/C═N bond formation via ring expansion. A series of 1-pyrroline derivatives are synthesized in moderate to good yields under mild conditions.