A Short Diastereoselective Total Synthesis of (±)-Vibralactone
Résumé
Vibralactone (1) is a terpenoid natural product, which inhibits pancreatic lipase (IC50 0.4 μg mL–1) with in vitro activity comparable to that of the FDA approved obesity therapeutic tetrahydrolipstatin (2, IC50 0.36 μg mL–1, Figure 1).(1, 2) Isolation of (−)-vibralactone was first reported by Liu et al. in 2006 by extraction from cultures of Basidiomycete Borestereum vibrans, leading to the elucidation of its unusual fused β-lactone structure and discovery of lipase inhibitory activity.(3) Shortly after its isolation, Snider and co-workers reported total syntheses of racemic and, subsequently, (−)-vibralactone employing an auxiliary controlled Birch reduction–prenylation strategy to form the C1 all-carbon quaternary center with high diastereoselectivity.(4, 5) Their asymmetric synthesis was achieved in 11 steps and 4.8% overall yield from a 2-methoxybenzamide derivative functionalized with a prolinol chiral auxiliary.