Synthesis of vinylic iodides for incorporation into the C17-C27 fragment of bryostatins

Gregson, Thomas J.; Thomas, Eric J.

doi:10.1016/j.tet.2017.04.048

“…[23,24] Thed isubstituted g-butenolide skeleton would be constructed by ar ing-opening/ring-closing/cross-metathesis (ROM/RCM/CM) reaction from the cyclobutenecarboxylate 12 and methacrolein, an extension of our ring-opening/ringclosing metathesis (ROM/RCM)o fc yclobutenecarboxylate derivatives for concise access to g-butenolides. [26] Oxidation of 14 with the Dess-Martin reagent provided the aldehyde 15,w hich was subjected to Takai-Utimoto olefination [27,28] to afford the alkenyl iodide 16 with high E selectivity. According to ak nown three-step procedure, d-(À)-pantolactone (13)w as converted into the alcohol 14.…”

mentioning

confidence: 99%

Total Syntheses of (+)‐Aquatolide and Related Humulanolides

Takao

¹

,

Kai

²

,

Yamada

³

et al. 2019

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The short, efficient total synthesis of (+ +)-aquatolide was achieved by ab iomimetic transannular [2+ +2] photocycloaddition, and provides the first example of constructing a5 /5/4/8-ring system from asteriscunolides.F urthermore,t he reaction leading to a5 /4/4/7-ring system, the originally proposed structure of aquatolide,w as also developed. This strategy achieved syntheses of five more humulanolides,( À)asteriscunolides A, C, D, and I, and (+ +)-tetradehydroasteriscanolide.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.org/10.1002/anie.201904404. Angewandte ChemieZuschriften Scheme 1. Construction of the asteriscunolide skeleton. DDQ = 2,3dichloro-5,6-dicyano-1,4-benzoquinone, DMSO = dimethylsulfoxide, LiHMDS = lithium bis(trimethylsilyl)amide, MPM = 4-methoxyphenylmethyl, THF = tetrahydrofuran.

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“…According to ak nown three-step procedure, d-(À)-pantolactone (13)w as converted into the alcohol 14. [26] Oxidation of 14 with the Dess-Martin reagent provided the aldehyde 15,w hich was subjected to Takai-Utimoto olefination [27,28] to afford the alkenyl iodide 16 with high E selectivity. Removal of the MPM group from 16 provided the allylic alcohol 17,w hich was acylatedw ith the acid anhydride 18 [25] to provide the cyclobutenecarboxylate 12.After optimization of the reaction conditions,wefound that the ROM/RCM/CM reaction of 12 proceeded in acascade manner to produce the desired (E)-a,b-unsaturated aldehyde 11 directly in good yield (60 %).…”

mentioning

confidence: 99%

Total Syntheses of (+)‐Aquatolide and Related Humulanolides

Takao

¹

,

Kai

²

,

Yamada

³

et al. 2019

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The short, efficient total synthesis of (+ +)-aquatolide was achieved by ab iomimetic transannular [2+ +2] photocycloaddition, and provides the first example of constructing a5 /5/4/8-ring system from asteriscunolides.F urthermore,t he reaction leading to a5 /4/4/7-ring system, the originally proposed structure of aquatolide,w as also developed. This strategy achieved syntheses of five more humulanolides,( À)asteriscunolides A, C, D, and I, and (+ +)-tetradehydroasteriscanolide.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.org/10.1002/anie.201904404. Angewandte ChemieZuschriften Scheme 1. Construction of the asteriscunolide skeleton. DDQ = 2,3dichloro-5,6-dicyano-1,4-benzoquinone, DMSO = dimethylsulfoxide, LiHMDS = lithium bis(trimethylsilyl)amide, MPM = 4-methoxyphenylmethyl, THF = tetrahydrofuran.

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Total Syntheses of (+)-Aquatolide and Related Humulanolides

Ogura,

Takao

2024

Modern Natural Product Synthesis

0

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Herein, the total syntheses of (+)-aquatolide, a humulane-derived sesquiterpenoid lactone, and five other related humulanolides are described. The key reactions in these syntheses are a cascade metathesis reaction of cyclobutenecarboxylate to construct a γ-butenolide with an unsaturated aldehyde side chain, an intramolecular Nozaki–Hiyama–Takai–Kishi reaction to form an all-trans-humulene lactone skeleton, and a biosynthesis-inspired [2 + 2] photocycloaddition to provide a bridged 5/5/4/8-ring system. A cycloaddition giving a 5/4/4/7-ring system was also found. In addition, biological studies were conducted using the synthesized samples.

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Synthesis of vinylic iodides for incorporation into the C17-C27 fragment of bryostatins

Cited by 4 publications

References 48 publications

Total Syntheses of (+)‐Aquatolide and Related Humulanolides

Total Syntheses of (+)‐Aquatolide and Related Humulanolides

Total Syntheses of (+)‐Aquatolide and Related Humulanolides

Total Syntheses of (+)-Aquatolide and Related Humulanolides

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