Stereoselective Synthesis of Allylic Alcohols via Substrate Control on Asymmetric Lithiation

Allylic alcohols are a privileged motif in natural product synthesis and new methods that access them in a stereoselective fashion are highly sought after. Toward this goal, we found that chiral acetonide-protected polyketide fragments performing the Hoppe–Matteson–Aggarwal rearrangement in the absence of sparteine with high yields and diastereoselectivities rendering this protocol a highly valuable alternative to the Nozaki–Hiyama–Takai–Kishi reaction. Various stereodyads and -triads were investigated to determine their substrate induction. The mostly strong inherent stereoinduction was attributed to a combination of steric and electronic effects

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

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