Pyrrolizidines VI: Stereoselective Synthesis of 1- and 2-(8S)-Pyrrolizidinones and Investigation of their Reductions with Complex Boron Hydrides
Starting with (S)-proline the title compounds are stereoselectively synthesized and subsequently reduced by complex boron hydrides.These reductions are studied with regard to their stereochemistry and possible mechanism.During the reduction of 1-(8S)-pyrrolizidinone (3) with lithium borohydride 1-(8S)-pyrrolizidinone borane 3a is isolated, this compound is assumed to be a reaction intermediate.