Organoselenium-based synthesis of oxygen-containing prostacyclins

Nicolaou, K. C.; Barnette, W. E.; Magolda, R. L.

doi:10.1021/ja00402a037

Cited by 25 publications

(14 citation statements)

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“…Also, exo,endo-conformation now results for (13). Analogously, the compounds ( 15) and (16) are also supposed to exist in endo,endoconformation as indicated by the absorption of C 9 at 84.2 and 83.0 ppm, respectively. In both cases the endo.endo-conformation of the rings makes intramolecular H-bond feasible.…”

Section: Resultsmentioning

confidence: 75%

“…In such conformation, steric repulsion between C 7 and ketal oxygen should be minimal. fc* (16) Fig. 1.…”

Section: Resultsmentioning

confidence: 99%

“…Inspection of the chemical shifts of lactone derivatives (11) to (16) suggests that the key role in determining their conformations belongs to the orientation of Cll and Cl 2 substituents. Examination of Dreiding models and Newman projections of compound (13) (and ( 14)) along Cl3-Cl2 bond (see Chart II) shows us that conformer I should be preferred in exo,endo-conformation of the rings, and conformer IV should be favoured in case of endo,endo-conformation of rings A and B.…”

Section: Resultsmentioning

confidence: 99%

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13с NMR Spectroscopy of Prostaglandins 2. Prostanoids With Oxygen at C9 and Their Intermediates

Lille¹,

Lippmaa²,

Lopp³

et al. 1986

Proceedings of the Academy of Sciences of the Estonian SSR. Che

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PROSTAGLANDIINIDE 13 C TMR SPEKTROSKOOPIA 2. Prostanoidid hapniku aatomiga С9 juures ja nende sünteesi vaheühendid Prostaglandiinide F 2(Z , F 2 p ja E 2 , prostatsükliinide li, I 2 ja karbatsükliini I 2 konformatsioonianalüüsi ning nende ühendite 13 C keemiliste nihete uurimisega on leitud sõltuvus 5-liikmelise ringi konformatsiooni ja I3 C nihete vahel. Selgus, et konformatsiooni muutumisega eksost endoks ehk prootonite 1,3-diaksiaalse orientatsiooni kadumisega kaasneb vastavate 13 C tuumade resonantssageduse nihkumine 2-3 ppm võrra tugevamasse välja. Seda sõltuvust kasutati prostanoidide sünteesi vaheühendite konformatsiooni määramiseks. Artiklis on toodud 102 prostanoidi ja nende vaheühendite 13 C keemilised nihked (neist 37 ühendi omad esmakordselt). Korrigeeriti mitmeid kirjanduses leiduvaid tulemusi.СПЕКТРОСКОПИЯ ЯМР 1 3 C ПРОСТАГЛАНДИНОВ 2. Простаноиды с кислородом при С9 и промежуточные продукты их синтеза Анализом констант спин-спинового взаимодействия 3 Jhh' и конформаций простагландинов F 2 и Ео и ряда простациклинов установлена зависимость химических сдвигов 13 С в этих соединениях от конформации 5-членных циклов. Обнаружено, что исчезновение протон-протонной ориентации, близкой к 1,3-диаксиальной, сопровождается сильнопольным сдвигом резонансов соответствующих ядер 13 С на 2-3 м. д. Эта закономерность использована для определения конформации промежуточных продуктов синтеза простаноидов. В статье приведены химические сдвиги 13 С 102 простаноидов и их промежуточных продуктов.

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Section: Resultsmentioning

confidence: 75%

“…In such conformation, steric repulsion between C 7 and ketal oxygen should be minimal. fc* (16) Fig. 1.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

13с NMR Spectroscopy of Prostaglandins 2. Prostanoids With Oxygen at C9 and Their Intermediates

Lille¹,

Lippmaa²,

Lopp³

et al. 1986

Proceedings of the Academy of Sciences of the Estonian SSR. Che

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“…125 Another set of powerful cyclizations developed in our laboratories are the phenylseleno (and phenylsulfeno) lactonizations and etherifications of olefinic acids and alcohols leading to lactones and cyclic ethers, respectively, employing PhSeX (or PhSX; X=Cl, Br). 126,127 Furthermore, our newly introduced at the time N-PSP (N-phenyl-selenophthalimide) and N-PSS (N-phenylselenosuccinimide) reagents were found useful in inducing phenylselenohydroxylation of olefins or phenylselenolactonizations and etherifications as shown in Figure 15f, g. [126][127][128] A number of these reagents and methods were proven enabling in our quest for prostacyclin analogues and related systems, 129,130 as well as in other laboratories for a variety of applications.…”

Section: Discovering and Developing New Synthetic Methods For The Advancement Of Organic Synthesismentioning

confidence: 99%

Total Synthesis Endeavors and Their Contributions to Science and Society: A Personal Account

Nicolaou

Rigol

2019

CCS Chem

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The advent of organic synthesis in the 19th century, serendipitous as it was, set in motion a revolution in science that continues to evolve into increasing levels of sophistication and to expand into new domains of science and technology for the benefits of science and society. Its evolution was always driven by the challenges posed by natural products, whose structures were becoming increasingly complex and diverse. In response to these challenges, synthetic organic chemists were prompted to sharpen their art to reach their target molecules, whose structures were often confirmed only after their synthesis in the laboratory through the art and science of total synthesis. The latter became the “locomotive” and the “flagship” of organic synthesis, for through this practice novel synthetic methods were discovered and invented, and also tested for their generality, applicability, and scope with regard to molecular complexity and diversity. The purpose of total synthesis has also evolved over the years to include aspects beyond the synthesis of the molecule and confirmation of its structure. In this article, we briefly review the evolution of total synthesis in terms of its power and reach and demonstrate its current state of the art that combines fundamentals with translational aspects through examples from our laboratories. The highlighted examples reflect the newly emerged paradigm of the discipline that includes—in addition to the total synthesis of the target molecule—structural elucidations, method discovery and development, design, synthesis, and biological evaluation of analogues for biology and medicine, and training of young students, preparing them for academic and industrial careers in the various disciplines that require knowledge and skills to practice the central science of chemical synthesis. Such disciplines include chemical biology, drug discovery and development, materials science and nanotechnology, and other endeavors whose fundamentals depend and rely on the structure of the molecule and its synthesis.

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“…This strategy has been extensively studied in substrates in which the heteroatom is O or NH, [1] and has been used to synthesise products with interesting biological properties. [2] Less attention has been paid to the synthesis of sulfur analogues by this approach, [3Ϫ16] even though replacement of O by S is a well-known strategy in the search for interesting new compounds.…”

Section: Introductionmentioning

confidence: 99%

Stereoselective Synthesis of Homochiral Substituted Tetrahydrothiophenes by Electrophile-Promoted Thioetherification

et al. 2003

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In this paper we study the electrophile-promoted cyclization of 2-sulfanyl-4-penten-1-ol and 1-sulfanyl-4-penten-2-ol derivatives as a way of preparing cyclic sulfides. The reaction is completely chemoselective and always proceeds by activation of the sulfur centre. The reaction of 2-sulfanyl-4-penten-1-ol derivatives proceeds by a 5-endo mode. Unsaturated thiol 6 undergoes iodine-promoted cyclothioetherification to give the tetrahydrothiophene 9 in moderate yields and with excellent regio-and stereoselectivity. However, when the reaction starts from the benzyl sulfide 7, a diastereomeric mixture of 9 and 10 is obtained in good yields. Selenium-promoted cyclization of unsaturated thioacetate 5 provides the [a] 209 selenyltetrahydrothiophene 12 or the sulfanyl acetate 13, depending on the selenium reagent used. On the other hand, electrophile-induced cyclization of 1-sulfanyl-4-penten-2-ol derivatives 23−25 depends on the electrophile used. Iodothioetherification of benzyl sulfide 25 followed by oxidation affords unsaturated sulfone 26 as a result of 6-endo-cyclization, dehydroiodination and oxidation. In contrast, selenothiocyclization of 24 with PhSeX results in the formation of the 5-exo tetrahydrothiophenes 29/30 and/or 31/32.

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Organoselenium-based synthesis of oxygen-containing prostacyclins

Cited by 25 publications

References 0 publications

13с NMR Spectroscopy of Prostaglandins 2. Prostanoids With Oxygen at C9 and Their Intermediates

13с NMR Spectroscopy of Prostaglandins 2. Prostanoids With Oxygen at C9 and Their Intermediates

Total Synthesis Endeavors and Their Contributions to Science and Society: A Personal Account

Stereoselective Synthesis of Homochiral Substituted Tetrahydrothiophenes by Electrophile-Promoted Thioetherification

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