The efficient and regioselective synthesis of the naphthoquinone core of streptovaricin U

Miyashita, Masaaki; Yamasaki, Takahiro; Shiratani, Tomonori; Hatakeyama, Susumi; Miyazawa, Masaaki; Irie, Hiroshi

doi:10.1039/a704596d

Cited by 17 publications

(4 citation statements)

References 11 publications

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“…This epoxy amide was then subjected to the introduction of a new methyl group via oxirane ring opening by the action of Gilman reagent, to give hydroxy amide 84 in a 73% yield, which was protected as its silyl ether 85 (Scheme ). It is worth note this latter compound contains the C-3/C-13 fragment of the ansa like antibiotic Streptovaricin U, , whose total synthesis we are currently investigating.…”

Section: Resultsmentioning

confidence: 99%

Epoxyamide-Based Strategy for the Synthesis of Polypropionate-Type Frameworks

et al. 2008

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A new approach to the stereoselective synthesis of polypropionate-type frameworks is reported utilizing reactions of amide-stabilized sulfur ylides with chiral aldehydes. To establish a new strategy for macrolide fragment synthesis, the stereoselectivity of these reactions in the construction of epoxy amides was the most important aspect of this study. In this aspect, we found a strong influence of the protecting groups employed in the starting aldehydes upon the stereochemical outcome of their reactions with the sulfur ylide 1. Thus, numerous aldehydes showed remarkable stereofacial differentiation, providing a major diastereoisomer, in contrast to others that displayed a poor or no stereoselectivity. Despite the difficulties encountered for some cases with respect to their diastereomeric yields, we were able to prepare various stereotetrads and stereopentads, thus enhancing the synthetic value of this new methodology for the preparation of typical polypropionate frameworks found in many natural products, in particular the macrolide class of antibiotics.

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Section: Resultsmentioning

confidence: 99%

Epoxyamide-Based Strategy for the Synthesis of Polypropionate-Type Frameworks

et al. 2008

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“…Ten years later, Rinehart et al was able to characterize the macrolactams by NMR, chemical derivatization studies, and X-ray analysis [ 71 ]. The structures of streptovaricin A 16a , D 16b , and U 16e ( Figure 5 ) consist of a napthoquinoid core and a polypropionate chain with nine contiguous stereogenic centers, five of which have a challenging all- anti relative configuration [ 72 ]. Interestingly, the streptovaricin U 16e ansa segment replaced the C10 carbomethoxy for a methyl group and streptovarcin A 16a has two tertiary alcohols at the C6 and C14 positions.…”

Section: Introductionmentioning

confidence: 99%

Epoxide-Based Synthetic Approaches toward Polypropionates and Related Bioactive Natural Products

Rodríguez-Berríos

Isbel

Bugarin

2023

IJMS

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Polypropionate units are a common structural feature of many of the natural products in polyketides, some of which have shown a broad range of antimicrobial and therapeutic potential. Polypropionates are composed of a carbon skeleton with alternating methyl and hydroxy groups with a specific configuration. Different approaches have been developed for the synthesis of polypropionates and herein we include, for the first time, all of the epoxide-based methodologies that have been reported over the years by several research groups such as Kishi, Katsuki, Marashall, Miyashita, Prieto, Sarabia, Jung, McDonald, etc. Several syntheses of polypropionate fragments and natural products that employed epoxides as key intermediates have been described and summarized in this review. These synthetic approaches involve enatio- and diastereoselective synthesis of epoxides (epoxy-alcohols, epoxy-amides, and epoxy-esters) and their regioselective cleavage with carbon and/or hydride nucleophiles. In addition, we included a description of the isolation and biological activities of the polypropionates and related natural products that have been synthetized using epoxide-based approaches. In conclusion, the epoxide-based methodologies are a non-aldol alternative approach for the construction of polypropionate.

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“…At first, diene 3 was prepared according to the reported procedure (Scheme 1). 8 The initial material butan-2-one (1) was treated with 1.5 equivalents of NaH (60% dispersion in mineral oil) and 3.0 equivalents of methyl formate in THF at -10 °C to give off-white solid, which was treated, after the solvent was replaced by DMF, with dimethyl sulfate to give (E)-3-methyl-4-methoxy-3-buten-2-one (2). After being purified by column chromatography over activated aluminum oxide (neutral), the butenone 2 was transformed into (E)-3-methyl-4-methoxy-2-[(trimethylsilyl)oxy]-1,3-butadiene (3) by treatment with 1.1 equivalents of LDA in THF at -78 °C followed by addition of Me 3 SiCl.…”

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confidence: 99%

An Efficient and Enantioselective Approach to 2,5-Disubstituted Dihydropyrones

Fu¹,

Gao²,

Yu³

et al. 2004

Synlett

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A highly efficient method for the formation of optically active 2,5-disubstituted dihydropyrones using catalytic enantioselective hetero-Diels-Alder reaction of (E)-3-methyl-4-methoxy-2-[(trimethylsilyl)oxy]-1,3-butadiene with aldehydes is presented. In the presence of 5 mol% chiral titanium(IV) complex, this catalytic reaction proceeded smoothly to afford corresponding dihydropyrones in moderate to excellent yields with high enantioselectivities (up to 99% ee).

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The efficient and regioselective synthesis of the naphthoquinone core of streptovaricin U

Cited by 17 publications

References 11 publications

Epoxyamide-Based Strategy for the Synthesis of Polypropionate-Type Frameworks

Epoxyamide-Based Strategy for the Synthesis of Polypropionate-Type Frameworks

Epoxide-Based Synthetic Approaches toward Polypropionates and Related Bioactive Natural Products

An Efficient and Enantioselective Approach to 2,5-Disubstituted Dihydropyrones

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The efficient and regioselective synthesis of the naphthoquinone core of streptovaricin U

Cited by 17 publications

References 11 publications

Epoxyamide-Based Strategy for the Synthesis of Polypropionate-Type Frameworks

Epoxyamide-Based Strategy for the Synthesis of Polypropionate-Type Frameworks

Epoxide-Based Synthetic Approaches toward Polypropionates and Related Bioactive Natural Products

An Efficient and Enantioselective Approach to 2,5-Disubstituted ­Dihydropyrones

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An Efficient and Enantioselective Approach to 2,5-Disubstituted Dihydropyrones