Alternative synthetic path to (−)-adalinine via a SmI2-promoted fragmentation of a 3-oxopyrrolidine derivative

A novel and stereocontrolled synthetic path to a coccinellid alkaloid, (−)-adalinine, was established by employing the reductive carbon-nitrogen bond cleavage reaction and subsequent recyclization of a 3-oxopyrrolidine derivative with samarium diiodide, as key steps, where water was found to be the best proton source.