Bioinspired Total Synthesis of (±)-Antroalbocin A enabled by a Photochemical 1,3-Acyl Shift

Abstract

The first bioinspired and protecting group free total synthesis of the antibacterial sesquiterpenoid antroalbocin A has been achieved in five linear steps from a literature-known intermediate with an overall yield of 6.7%. An intramolecular Robinson annulation gave rapid access to the tricyclic enone as starting material for a photochemical domino process of deconjugation and sigmatropic 1,3-acyl shift. Herein we further describe studies towards the use of photolytic sigmatropic 1,3-acyl shifts in the synthesis of bridged terpenoid building blocks.Antroalbocin A (1), isolated in 2018 from the higher fungus Antrodiella albocinnamomea by Liu and co-workers, is a new antibacterial sesquiterpenoid. [1] Its unique structure shows a novel bridged 5/5/6 tricyclic system with three all carbon quaternary centers. Two of them are located in both bridgehead positions.

Total Synthesis of (−)-Antroalbocin A Enabled by a Strain Release-Controlled Photochemical 1,3-Acyl Shift

“…Antroalbocin A ( 1 ), isolated in 2018 from the higher fungus Antrodiella albocinnamomea by Liu and co-workers, is a new antibacterial sesquiterpenoid. Its unique structure shows a novel bridged 5/5/6 tricyclic system with three all-carbon quaternary centers (Figure ), two of which are located in bridgehead positions.…”