Stereoselective Total Synthesis of the Nonenolide (+)-Microcarpalide

Banwell, Martin G.; Loong, David T. J.

doi:10.3987/com-03-s(p)71

Cited by 26 publications

(17 citation statements)

References 7 publications

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“…194 The β-oxygen problem noted with stoichiometric reactions is not observed. 195 The byproducts of the reaction are iodobenzene, acetic acid, and TEMPO. TEMPO is removed by washing with sodium thiosulfate, which reduces TEMPO to the water-soluble hydroxylammonium sulfate and the acetic acid is removed by washing with aqueous sodium bicarbonate.…”

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confidence: 99%

Oxoammonium‐ and Nitroxide‐Catalyzed Oxidations of Alcohols

2009

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The discovery in 1959 of stable nitroxide‐based free radicals such as the prototypical 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) led to their use as electron spin resonance (ESR) spin labels in chemistry, biomedicine, and materials science. These nitroxides are prepared by the oxidation of secondary amines that contain no hydrogen atoms on the alpha‐carbons. The unique redox properties of nitroxides enable their use as oxidants in organic synthesis. The varied preparation and uses of oxoammonium salts as stoichiometric oxidants for alcohols are one subject of this review. Oxoammonium ions as oxidants for alcohols have a number of advantages, for example, the method is heavy‐metal free and some of the reactions can be performed in water or aqueous mixtures. A few side reactions are associated with these oxidations. The most serious is the fast reaction of the oxoammonium ion with free amines The several ways these oxidation reactions can be carried out are discussed in detail. They are: Oxidations using stoichimetric quantities of preformed oxoammonium salts carried out in either acidic, neutral, or basic conditions; reactions in which stoichiometric quantities of oxoammonium salts are generated in situ by disproportionation of a nitroxide in the presence of a strong acid; nitroxide‐catalyzed oxidations using a secondary oxidant; efficient nitroxide‐catalyzed oxidations of primary alcohols to carboxylic acids; and oxidations of primary alcohols or hemiacetals that can lead to lactones.

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confidence: 99%

Oxoammonium‐ and Nitroxide‐Catalyzed Oxidations of Alcohols

2009

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“…2 By virtue of such a peculiar biological activity, the apparently simple, but yet stereochemically demanding macrocyclic structure of this new fungal metabolite has aroused the interest of the chemical community, and a few total syntheses have appeared accordingly. [3][4][5][6][7] In the course of our previous total synthesis of microcarpalide, we had successfully exploited Matteson's asymmetric homologation 8 to insert sequentially the two stereocentres at positions 10 and 1 0 with the required S absolute configuration, using (C)-pinanediol as the chiral director. 5 Along this line, we reasoned that the two remaining stereocentres, namely 5R and 6R, could be also installed likewise by an enantioselective approach featuring the stereoselective homologation of suitable chiral boronic esters, rather than from the chiral pool.…”

Section: Introductionmentioning

confidence: 99%

“…5 Along this line, we reasoned that the two remaining stereocentres, namely 5R and 6R, could be also installed likewise by an enantioselective approach featuring the stereoselective homologation of suitable chiral boronic esters, rather than from the chiral pool. [3][4][5][6] Hence, a modified retrosynthetic route was devised, as outlined in Scheme 1.…”

Section: Introductionmentioning

confidence: 99%

Enantioselective total synthesis of (−)-microcarpalide

et al. 2005

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“…Banwell's group (2004, entmicrocarpalide), 44) Chavan's group (2005), 45) and Fürst-ner's group (2007) 46) employed precursor 18 (or ent-18), the same intermediate as in Marco's synthesis. 22,23) Synthesis of ent-microcarpalide by Banwell and Loong is shown in Scheme 2 [5].…”

Section: Other Syntheses Of Microcarpalide Employing Rcmmentioning

confidence: 99%

“…22,23) Synthesis of ent-microcarpalide by Banwell and Loong is shown in Scheme 2 [5]. 44) They constructed the intermediate ent-18 by cross metathesis 4,19) of , -unsaturated ester 44 using 2nd-generation Grubbs catalyst 20) under ethylene, because direct methylenation of hemiacetal 43 (conversion to ent-18) was not successful, and RCM of , -unsaturated ester 44 did not proceed. 47) Hemiacetal 43 was synthesized from alcohol 41 and acid 42, whose stereocenters originated in Sharpless AD 30,31) and (S)-malic acid respectively.…”

Section: Other Syntheses Of Microcarpalide Employing Rcmmentioning

confidence: 99%

Synthetic Studies of Natural 10-Membered Lactones, Mueggelone, Microcarpalide, and Sch 642305, Which Have Interesting Bioactivities

Ishigami

2009

Bioscience, Biotechnology, and Biochemistry

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A number of 10-membered lactones have been isolated as secondary metabolites, and many of them have interesting and potent activities. Because of synthetic and biological interests, many synthetic studies of these compounds have been made. This review summarizes synthetic approaches to three natural 10-membered lactones, mueggelone, microcarpalide, and Sch 642305. Mueggelone is an inhibitor of fish development, microcarpalide is a microfilament disrupting agent, and Sch 642305 is an inhibitor of bacterial DNA primase.

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Stereoselective Total Synthesis of the Nonenolide (+)-Microcarpalide

Cited by 26 publications

References 7 publications

Oxoammonium‐ and Nitroxide‐Catalyzed Oxidations of Alcohols

Oxoammonium‐ and Nitroxide‐Catalyzed Oxidations of Alcohols

Enantioselective total synthesis of (−)-microcarpalide

Synthetic Studies of Natural 10-Membered Lactones, Mueggelone, Microcarpalide, and Sch 642305, Which Have Interesting Bioactivities

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