Stereocontrolled Synthesis of Adjacent Acyclic Quaternary-Tertiary Motifs: Application to a Concise Total Synthesis of (−)-Filiformin

Lithiation/borylation methodology has been developed for the synthesis of acyclic quaternary‐tertiary motifs with full control of relative and absolute stereochemistry, thus leading to all four possible isomers of a stereodiad. A novel intramolecular Zweifel‐type olefination enabled acyclic stereocontrol to be transformed into cyclic stereocontrol. These key steps have been applied to the shortest enantioselective synthesis of (−)‐filiformin to date (9 steps) with full stereocontrol. True to (fili)form: Lithiation/borylation methodology has been developed for the synthesis of acyclic quaternary‐tertiary motifs with full control of relative and absolute stereochemistry, thus leading to all four possible isomers of a stereodiad. A novel intramolecular Zweifel‐type olefination enabled acyclic stereocontrol to be transformed into cyclic stereocontrol. These key steps were applied to the enantioselective synthesis of (−)‐filiformin.