Construction of the Azacyclic Core of Tabernaemontanine-Related Alkaloids via Tandem Reformatsky-Aza-Claisen Rearrangement.

A divergent synthetic methodology for a tabernaemontanine-related alkaloid was developed. The synthetic route features practical improvements in the Pictet-Spengler cyclization for the tetrahydro-β-carboline intermediate and an unprecedented tandem Reformatsky-aza-Claisen rearrangement to create the core carbon skeleton and stereochemistries of tabernaemontanine-related alkaloids.