Divergent synthesis of (+)-tanikolide and its analogues employing stereoselective rhodium(II)-catalyzed reaction

Abstract

In this study, we described the divergent synthesis of (+)-tanikolide and its analogues, such as (4S)-and (4R)-hydroxytanikolides, and nortanikolide, employing a stereoselective dirhodium(II)-catalyzed reaction to construct the quaternary chiral center of tanokolides. The key steps involve (a) a dirhodium(II)-catalyzed oxonium ylide formation-[2,3]-sigmatropic rearrangement, (b) an N-heterocyclic carbene-catalyzed ring-expansion lactonization of tetrahydrofurfural, or (c) an oxidative cleavage of tetrahydrofuran-5-methanol to γ-lactone using a 2-iodobenzamide catalyst. This route would provide high flexibility for analogue synthesis because the long side chain can be introduced at a later stage in the synthesis.

Sulfonyl Hydrazides in Organic Synthesis: A Review of Recent Studies

“…They were successfully used for the total synthesis of natural products, which included Brasilicardins A and C, (+)‐Frondosin A, (+)‐Tanikolide, Lundurines A−C, Onoseriolid, Isobolivianine, (−)‐Crinipellin A, Panaginsene, Echinopines, (+)‐ and (−)‐Isolaurepan, (−)‐Strychnofoline, (−)‐Clovan‐2,9‐dione, (+)‐Sarcophytin, [2 ° ] (+)‐Chatancin, [2 ° ] (−)‐3‐Oxochatancin, [2 ° ] (+)‐Cyperolone . In these cases, TsNHNH 2 reacted with aldehydes (or ketones) to form hydrazones that underwent cycloaddition or reduction subsequently. Banford‐Stevens reaction and Shapiro reaction were reported in this decade.…”

“…In these cases, TsNHNH 2 reacted with aldehydes (or ketones) to form hydrazones that underwent cycloaddition or reduction subsequently. Banford‐Stevens reaction and Shapiro reaction were reported in this decade.…”

Palladium-Catalyzed Asymmetric Allylic C–H Alkylation of 1,4-Dienes with Cyclic β-Keto Esters

“…Tanikolide is a brine-shrimp toxin and antifungal marine natural product, isolated from the lipid extract of the cyanobacterium . Commencing with the asymmetric allylic alkylation, an enantioselective formal synthesis of (−)-tanikolide was accomplished (Scheme ). Chiral α,α-disubstituted β-keto ester 3ab in 83% ee, obtained from the asymmetric allylic C–H alkylation of cyclic β-keto ester 1a and 1,4-diene 2b , was treated with LiAlH 4 to furnish the diol 4 , which was then hydrogenated to give diol 5 .…”

Metathesis Reactions in Natural Product Fragments and Total Syntheses

“…After a series of steps, 726 was transformed to penaresidin B. On the other hand, Yakura and co‐workers reported the divergent synthesis of (+)‐tanikolide 731 (Scheme 113), a brine‐shrimp toxic and antifungal δ ‐lactone liked to a long alkyl chain and hydroxymethyl group, extracted from the marine cyanobacterium Lyngbya majuscule [294] . Rhodium‐(II) derived [2,3]‐sigmatropic rearrangement of diazoketoester 728 resulted in the formation of dihydrofuranone 729 .…”

“…On the other hand, Yakura and co-workers reported the divergent synthesis of (+)-tanikolide 731 (Scheme 113), a brine-shrimp toxic and antifungal δ-lactone liked to a long alkyl chain and hydroxymethyl group, extracted from the marine cyanobacterium Lyngbya majuscule. [294] Rhodium-(II) derived [2,3]-sigmatropic rearrangement of diazoketoester 728 resulted in the formation of dihydrofuranone 729. Next, CM of 729 with 1-decene in presence of G-II catalyst furnished an alkene compound 730 in remarkable yield after several steps, 730 was converted to the desired (+)-tanikolide.…”