A Unified Strategy for the Synthesis of Natural Products Containing δ‐Hydroxy‐γ‐ Lactones through a Photoredox ATRA Reaction.

Abstract

A unified strategy for the synthesis of natural products containing δ‐hydroxy‐γ‐lactones as the main core is reported. This strategy is based on a photocatalyzed radical ionic sequence for the preparation of γ‐lactones. Depending on the necessities of the synthetic targets, the reaction conditions can be adjusted to access a diastereoisomeric mixture or a single diasteroisomer of the lactones. Also, δ‐lactones can be prepared by this method. The utility of this procedure was demonstrated by the total synthesis of five natural products.

Synthetic Studies towards Pheromones by Cyanide‐Catalyzed Ring Transformation of α‐Hydroxy‐β‐oxoesters to δ‐Valerolactones

“…It was therefore named Baeyer‐Villiger oxidation (BVO) in honor of its discoverers [14] . Very recently, an interesting photocatalyzed radical ionic sequence has been reported to access γ‐ as well as δ‐lactones [15] …”

“…[14] Very recently, an interesting photocatalyzed radical ionic sequence has been reported to access γas well as δ-lactones. [15] δ-Lactones with a substituent in the δ-position came into the focus of our research interest because we had lately discovered a new cyanide-catalyzed [16] ring-transformation of αhydroxy-β-oxoesters 8 to δ-valerolactones 9. The conversion of starting material 8 a with 0.1 equiv.…”