DEVELOPMENT OF SAMARIUM DIIODIDE-PROMOTED REDUCTIVE CARBON-NITROGEN BOND CLEAVAGE REACTION OF α-AMINO CARBONYL COMPOUNDS: APPLICATION TO THE SYNTHESIS OF BIOLOGICALLY ACTIVE ALKALOIDS

Samarium diiodide (SmI2) is a mild and selective one electron transfer reagent, and has become an important tool for developing a variety of useful and unique transformations. SmI2 has been utilized in a wide range of synthetic transformations ranging from interconversion of functional groups to carbon-carbon bond forming reactions. Among the various reactions developed for SmI2, we focused our attention on its use for fragmentation reactions. We have already established a regioselective carbon-carbon bond cleavage reaction of gamma-halo carbonyl compounds, and its utilization in the synthesis of various types of biologically active natural products. However, a SmI2-promoted reductive carbon-nitrogen bond cleavage reaction has received relatively little attention. In this review article, we would like to describe a general carbon-nitrogen bond cleavage reaction of alpha-amino carbonyl compounds and the utilization of this methodology in the synthesis of a number of bioactive alkaloids, since this reaction proceeds in relatively high yield under mild reaction conditions.