Total synthesis of (+)-dienomycin C

Yokoyama, Hajime; Hayashi, Yuko; Nagasawa, Yumi; Ejiri, Hiromi; Miyazawa, Masaaki; Hirai, Yoshiro

doi:10.1016/j.tet.2010.08.048

Cited by 17 publications

(5 citation statements)

References 10 publications

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“…Replacement of the bulky ligand with n -Bu 3 P gave a mixture of diastereomers (dr 1:1.5), and a switch from Cs 2 CO 3 to a stronger base led to substantial decomposition. In the synthesis of (+)-dienomycin C, Hirai and co-workers utilized a direct palladium-catalyzed intramolecular amination of an allylic alcohol to furnish the requisite piperidine skeleton (Scheme b) . Treatment of 194 - 3 with PdCl 2 (CH 3 CN) 2 afforded piperidine 194 - 5 as a single isomer in 82% yield.…”

Section: Diastereoselective Metal-catalyzed Allylic N-alkylation (Fig...mentioning

confidence: 99%

“…In the synthesis of (+)-dienomycin C, Hirai and co-workers utilized a direct palladium-catalyzed intramolecular amination of an allylic alcohol to furnish the requisite piperidine skeleton (Scheme 194b). 751 Treatment of 194-3 with PdCl 2 (CH 3 CN) 2 afforded piperidine 194-5 as a single isomer in 82% yield. It was postulated that the stereochemical outcome was controlled through the chair transition state 194-4 to minimize steric repulsion between the carbamate and the π-allyloxy−palladium complex.…”

Section: Diastereoselective Metal-catalyzedmentioning

confidence: 99%

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Cutting-Edge and Time-Honored Strategies for Stereoselective Construction of C–N Bonds in Total Synthesis

et al. 2016

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The main objective of this review is to provide a comprehensive survey of methods used for stereoselective construction of carbon-nitrogen bonds during the total synthesis of nitrogen-containing natural products that have appeared in the literature since 2000. The material is organized by specific reaction in order of decreasing number of applications in natural product synthesis. About 800 total syntheses of natural products with stereogenic carbon-nitrogen bonds described since 2000 have been reviewed.

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Section: Diastereoselective Metal-catalyzed Allylic N-alkylation (Fig...mentioning

confidence: 99%

Section: Diastereoselective Metal-catalyzedmentioning

confidence: 99%

Cutting-Edge and Time-Honored Strategies for Stereoselective Construction of C–N Bonds in Total Synthesis

et al. 2016

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“…Scheme 3 depicts the synthesis of terminal olefin fragment 8 , accessed from the known [4] allyl alcohol 13 in 4 steps from readily available 1,3‐propanediol. Thus, the allyl alcohol 13 upon Sharpless asymmetric epoxidation [(−)‐DIPT, Ti(O i Pr) 4 , TBHP, 4‐Å MS, CH 2 Cl 2 , −20 °C] gave the corresponding epoxy alcohol 14 in 80 % yield [5] . The epoxy alcohol 14 was then converted to the corresponding iodide [6] (I 2 /PPh 3 /imidazole), which on Zn‐mediated reductive elimination afforded the secondary chiral allylic alcohol 15 .…”

Section: Resultsmentioning

confidence: 99%

“…Thus, the allyl alcohol 13 upon Sharpless asymmetric epoxidation [(À )-DIPT, Ti(O i Pr) 4 , TBHP, 4-Å MS, CH 2 Cl 2 , À 20 °C] gave the corresponding epoxy alcohol 14 in 80 % yield. [5] The epoxy alcohol 14 was then converted to the corresponding iodide [6] (I 2 /PPh 3 /imidazole), which on Zn-mediated reductive elimination afforded the secondary chiral allylic alcohol 15. [7] Then, allyl alcohol 15 was protected as its methyl ether (MeI, NaH, THF, rt) followed by TBS deprotection using TBAF to give the corresponding primary alcohol 16 (88 % yield).…”

Section: Synthesis Of Polyketide Fragment 4 (First Approach)mentioning

confidence: 99%

Studies Directed Toward the Total Synthesis of Nannocystin A

2022

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A full account of our efforts directed toward the stereoselective total synthesis of nannocystin A, a macrocyclic myxobacterial metabolite, is presented. In this endeavor, we have attempted two distinct synthetic routes to access polyketide fragment (C1‐C11) of macrocyclic depsipeptide (21‐membered) natural product from readily accessible building blocks 1,3‐propanediol and benzaldehyde employing Evans aldol, CBS reduction, Heck cross‐coupling, and Sharpless asymmetric epoxidation as key transformations. Ultimately, accomplished the synthesis of the complete skeleton (21‐membered precursor for macrocyclic depsipeptide) of the nannocystin A possessing desired stereochemistry and functional groups.

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“…According to the literature reporting catalyzed allylic amination to form the six‐membered ring of piperidines,[3c], dihydroquinolines or substituted amines, the alcohol function can be free or activated as a carbonate or an acetate. In order to optimize the reaction conditions for our TP synthesis, we decided to start from either alcohol 3a or methyl carbonate 4a (Table ).…”

Section: Resultsmentioning

confidence: 99%

Diastereoselective Synthesis of 2,6‐Disubstituted‐1,2,3,6‐Tetrahydropyridines through a Palladium‐Catalyzed Intramolecular Allylic Amination

et al. 2019

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An efficient synthesis of 2,6-disubstituted-1,2,3,6tetrahydropyridines is reported, featuring a highly diastereoselective palladium-catalyzed intramolecular allylic amination Scheme 1. Previous work toward the synthesis of 2,6-disubstituted-piperidines. Current methodology toward the preparation of 2,6-disubstituted-TP.[a] 7686 from non-activated alcohols. This method allowed a straightforward access to 2,6-trans-1,2,3,6-tetrahydropyridines with de up to 100 % under mild conditions, in moderate to good yields.Mitsunobu [1c] reactions, allyl nitrone cyclization, [7] aza-[2,3]-Wittig rearragements of vinylaziridines [8] or diastereoselective C-H functionalization. [9] However, methods leading to trans-2,6disubstituted-TP/piperidines are less reported, because the trans relative configuration is thermodynamically disfavored. [10] For example, trans-2,6-disubstituted-TP/piperidines can be obtained by C-N bond formation and ring closure, the TP substituents at 2-and 6-positions being already present in the structure. These methods employed allylic alcohols or their activated counterparts as precursors, and used Brønsted acid conditions, S N 2 or Mitsunobu reactions affording nitrogen attack, to form the unsaturated 6-membered ring.Knowing the importance of stereocenter configuration for biological activities, the development of new stereoselective syntheses of trans-2,6-disubstituted-TP/piperidines remains an important challenge. During our previous studies, we developed a methodology to prepare stereoselectively either 2,6-cis or 2,6-trans-disubstituted-piperidines via a Michael-type cyclization. [11] This methodology used ′-carbamate-α, -unsaturated ketone [3a] as a key precursor. We further envisioned that 2,6disubstituted-TP could be formed via a palladium-catalyzed Eur.7691 saturated aqueous NH 4 Cl solution and extracted 3 times with EtOAc. Then the organic layer was dried with MgSO 4 , filtered, and concentrated under vacuum. The crude was purified by silica gel column chromatography as described in the corresponding synthetic procedure to give the ketone 2a-x. Benzyl (R,E)-(6-Oxo-8-phenyloct-7-en-4-yl)carbamate (2e):was prepared from benzyl (R)-(1-(diethoxyphosphoryl)-2-oxoheptan-4yl)carbamate 1e (1 g, 2.50 mmol). The crude product was purified by silica gel column chromatography (SiO 2 , 100 % cyclohexane to 8:2 cyclohexane/EtOAc) providing 2e as a white solid in 91 % yield (800 mg, 2.28 mmol). TLC R f = 0.49 (cyclohexane/EtOAc, 7:3); Mp 93°C; 1 H NMR (400 MHz, CDCl 3 ) δ = 7.62-7.48 (m, 3H), 7.42-7.37 (m, 3H), 7.36-7.27 (m, 5H), 6.72 (d, J = 16.1 Hz, 1H), 5.27 (d, J = 8.7 Hz, 1H), 5.08 (s, Benzyl (S,E)-(3-Oxo-1,5-diphenylpent-4-en-1-yl)carbamate 2f:was prepared from benzyl (S)-(4-(diethoxyphosphoryl)-3-oxo-1phenylbutyl)carbamate 1f (100 mg, 0.231 mmol). The crude product was purified by silica gel column chromatography (SiO 2 , 100 % cyclohexane to 8:2 cyclohexane/EtOAc) providing 2f as a beige solid in 81 % yield (71.6 mg, 0.186 mmol). TLC R f = 0.47 (cyclohexane/ EtOAc, 7:3); Mp 114°C; 1 H NMR (400 MHz,...

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Total synthesis of (+)-dienomycin C

Cited by 17 publications

References 10 publications

Cutting-Edge and Time-Honored Strategies for Stereoselective Construction of C–N Bonds in Total Synthesis

Cutting-Edge and Time-Honored Strategies for Stereoselective Construction of C–N Bonds in Total Synthesis

Studies Directed Toward the Total Synthesis of Nannocystin A

Diastereoselective Synthesis of 2,6‐Disubstituted‐1,2,3,6‐Tetrahydropyridines through a Palladium‐Catalyzed Intramolecular Allylic Amination

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