Stereoselective Total Syntheses of Acutifolone A, Bisacutifolone A and B, Pinguisenol, and Isonaviculol

Stereoselective total
syntheses of pinguisane type of sesquiterpenoids
are described following a unified approach using a chiral building
block derived from (R)-pulegone. The functionality
embodied in the key intermediate enables their facile elaboration
into more complex structures of biological relevance such as acutifolone
A (9 steps, 22% overall yield) and bisacutifolone A and B (6 and 8%,
respectively) following Furukawa’s modified Simmons–Smith
cyclopropanation, Luche reduction, Saegusa–Ito oxidation, pyridinium
chlorochromate-mediated 1,3-oxidative transposition, and Diels–Alder
dimerization as key steps.