Total syntheses of Ganoderma-derived meroterpenoids, (-)-oregonensin A, (-)-chizhine E, (-)-applanatumol U, and (-)-ent-fornicin A

In this study, we report the total syntheses of Ganoderma-derived meroterpenoids, (-)-oregonensin A, (-)-chizhine E, (-)-applanatumol U, and (-)-ent-fornicin A. The 3-alkyl-5-aryl-gamma-butenolide skeleton, a common motif of these meroterpenoids, was constructed through the enantioselective reductive lactonization of the gamma-keto ester, alkylation, and sulfoxide-beta-syn-elimination. This flexible approach enabled enantioselective access to these meroterpenoids with the longest linear sequence of 6-8 steps, and in 21-36% overall yield, respectively.

Automated summary

In this study, total syntheses of four Ganoderma-derived meroterpenoids were reported. A flexible approach was developed to construct the 3-alkyl-5-aryl-gamma-butenolide skeleton, a common motif of these meroterpenoids. The target compounds were synthesized with enantioselective access and moderate overall yields.