Synthesis of Aspidodispermine via Pericyclic Framework Reconstruction
F. Reuß, P. Heretsch – 2020
A divergent approach to the pyrroloquinoline scaffold as present in the class of aspidosperma alkaloids was developed. As a case study, abundant and renewable nicotinic acid was transformed via pericyclic framework reconstruction into aspidodispermine, a unique member of pyrroloquinoline alkaloids. The sequence comprises of a [2+2]-photocycloaddition, a Ramberg–Bäcklund contraction, and a strain-promoted formal electrocyclic rearrangement of a bicyclo[2.2.0]hexene and is potentially extendable to pyrroloindole scaffolds as present in the ibophyllidine alkaloids.