Total Synthesis of ent-Plagiochianin B

Abstract

An enantioselective total synthesis of plagiochianin B is described that employs (+)-3-carene as its point of departure and delivers the enantiomer of the natural product. Key features of the synthesis include a palladium-mediated regioselective oxidative cleavage of an olefin residing on a pyridine derived from a 6πazatriene electrocyclization.

Bioinspired Total Synthesis of (+)‐Euphorikanin A

“…[27] Finally, removal of the acetyl in 29 with KOH in MeOH accompanied with the simultaneous benzilic acid type rearrangement furnished (+)-euphorikanin A (1). All analytical data ( 1 H NMR, 13 C NMR, HRMS, X-ray crystal, [29] [α] D ) of synthetic 1 matched with that reported for the natural product.…”

Vicinal ketoesters – key intermediates in the total synthesis of natural products

“…In the final step of the synthesis of (+)-euphorikanin A ( 16), an ingenane-derived diterpenoid with a 5/6/7/3-fused tetracyclic carbon skeleton, Carreira et al used an intramolecular nucleophilic addition of an alkenyl metal species to the α-ketoester 15 (Scheme 3) [6]. The ketoester 15 was synthesized by a chiral pool approach starting from (+)-3-carene derived cycloheptenone 13 [7,8] and aldehyde 12 (accessible from (R)-Roche ester [9]) via the γ-lactone 14. The ketoester moiety was established by an enolate hydroxylation with Davis' oxaziridine and subsequent oxidation using Dess-Martin periodinane.…”

Bioinspired Total Synthesis of (+)‐Euphorikanin A

“…In fact, Yamakawa and co-workers had reported the preparation of 11 from (+)-3-carene (12) in 1984. [12] In 2021, the synthetic routine was independently modified by the groups of Wood [13] and Carreira, [6] and cycloheptenone 11 was obtained in 19 % overall yield. In our case, we designed and developed a new routine of 11 which enabled us to access 11 in 38 % overall yield (Scheme 3).…”