Total syntheses and stereochemical reassignments of mollenines A and B

Shiomi, Shinya; Wada, Kohei; Umeda, Yuhei; Kato, Hikaru; Tsukamoto, Sachiko; Ishikawa, Hayato

doi:10.1016/j.bmcl.2018.01.065

Cited by 5 publications

(4 citation statements)

References 15 publications

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“…Outstanding examples of this sort of secondary metabolites contain the pyrroloindoline unit fused to a diketopiperazine, such as (−)-5- N -acetylardeemin ( 1 ), (−)-roquefortine C ( 4a ), (−)-fructigenine A ( 4b ), (−)-penicimutatin A ( 4c ), and (+)-novoamauromine ( 12 ) (Figure ), − or to a diketomorpholine ring, as in (−)-javacunine A ( 5 ) and (−)-javacunine B ( 6 ) (Figure ). , Less common molecular skeletons possess the pyrroloindoline moiety connected to a benzodiazepinedione framework, as in the family of aszonalenin alkaloids ( 2 and 3 , Figure ), − the related congeners epi -aszonalenins ( 7 and 8 , Figure ), and the most recently reported asnovolenines ( 9 and 10 , Figure ).…”

Section: Introductionmentioning

confidence: 99%

Total Synthesis of the Proposed Structure of (−)-Novofumigatamide, Isomers Thereof, and Analogues. Part I

et al. 2022

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The total synthesis of the suggested structure of (−)-novofumigatamide, a natural product containing a C3-reverse prenylated N -acetyl- exo -hexahydropyrrolo[2,3- b ]indole motif fused to a 10-membered ring lactam, was achieved using the macrolactam formation in advance of a diastereoselective bromocyclization and reverse prenylation steps. Since the NMR data of the synthetic sample did not match those of the natural product, the endo -bromo precursor of a N -Boc analogue and additional diastereomers derived from l -Trp were also synthesized. Five alternative synthetic routes, which differed in the order of final key steps used for the construction of the 10-membered ring lactam and the hexahydropyrrolo[2,3- b ]indole framework within the polycyclic skeleton and also in the amide bond selected for the ring-closing of the macrolactam, were thoroughly explored. Much to our dismay, the lack of spectroscopic correlations between the proposed structure of natural (−)-novofumigatamide and the synthetic products suggested a different connectivity between the atoms. Additional synthetic efforts to assemble alternative structures of the natural product and isomers thereof (see accompanying paper; DOI: ) further highlighted the frustrating endeavors toward the identification of a natural product.

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Section: Introductionmentioning

confidence: 99%

Total Synthesis of the Proposed Structure of (−)-Novofumigatamide, Isomers Thereof, and Analogues. Part I

et al. 2022

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“… Reagents and conditions: (a) DMAP, BOP reagent, CH 2 Cl 2 , 2 or MeSO 3 H, CHCl 3 , Δ; 3 (b) DEAD, THF; 2 (c) Amberlyst 15, toluene, Δ, 2 or p -TsOH, toluene, Δ; 4 , 5 (d) p -TsOH, toluene, Δ, 4 or DBU, MS 4 Å, toluene; 6 (e) NaHCO 3 , DMF, Δ, 7 , 8 or TEA, DMF, Δ, 2 , 9 or DIPEA, CHCl 3 , Δ, 10 or (1) NaOH, EtOH, H 2 O, (2) H 2 SO 4 ; 2 (f) DIPEA, DMSO, 11 or (1) K 2 CO 3 , H 2 O, (2) HCl, 12 or (1) NaOH, EtOH, H 2 O, (2) HCl. 2 …”

Section: Solution-phase Synthesesmentioning

confidence: 99%

“…Mollenines A ( 49 ) and B ( 50 ) were isolated from the sclerotioid ascostromata of Eupenicillium molle . The total synthesis of 49 was realized either by the preparation of a prenylated pyrrolidinoindoline ester from tryptophan and the final connection with leucic acid or by a one-pot reaction of the DKM composed of tryptophan and leucic acid with a vinyl cyclopropane reagent . Mollenine A possessed cytotoxic and antibacterial activity against Bacillus subtilis .…”

Section: Natural Productsmentioning

confidence: 99%

Diketomorpholines: Synthetic Accessibility and Utilization

Gütschow

2021

ACS Omega

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Diketomorpholines (DKMs; morpholine-2,5-diones) possess a six-membered ring with a lactone and lactam moiety and belong to the family of cyclodepsipeptides. In this review, the synthetic accessibility of DKMs is summarized and their utilization, in particular, for ring-opening polymerization reactions, is highlighted. The occurrence of the DKM scaffold in natural products encompasses small monocyclic compounds but also complex, polycyclic representatives with a fused DKM ring.

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“…Indoline with a heteroaromatic bicyclic scaffold is a privileged structural motif, which presents in many natural and biologically active compounds, such as (−)-Mersicarpine, (−)-Isatisine A, and Mollenine A (Figure ). Catalytic asymmetric dearomatization (CADA), the term coined by You, of indole derivatives has been deemed to be an attractive strategy to readily access sophisticated spiro or fused polycyclic indoline scaffolds with stereochemistry .…”

mentioning

confidence: 99%

Pd-Catalyzed Asymmetric Dearomatization of Indoles via Decarbonylative Heck-Type Reaction of Thioesters

et al. 2020

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We report herein a palladium-catalyzed ligandpromoted asymmetric dearomatization of indoles via the decarbonylation of thioesters and the subsequent reductive Heck reaction. This protocol provides a facile and efficient way to construct an aza-quaternary stereocenter at the C2 position of indolines. A variety of functional groups and substitutions could be well tolerated, affording the substituted indolines with high enantioselectivities.

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Total syntheses and stereochemical reassignments of mollenines A and B

Cited by 5 publications

References 15 publications

Total Synthesis of the Proposed Structure of (−)-Novofumigatamide, Isomers Thereof, and Analogues. Part I

Total Synthesis of the Proposed Structure of (−)-Novofumigatamide, Isomers Thereof, and Analogues. Part I

Diketomorpholines: Synthetic Accessibility and Utilization

Pd-Catalyzed Asymmetric Dearomatization of Indoles via Decarbonylative Heck-Type Reaction of Thioesters

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