Stereoselective synthesis of the C79–C97 fragment of symbiodinolide

Takamura, Hiroyoshi; Fujiwara, Takayuki; Kadota, Isao; Uemura, Daisuke

doi:10.3762/bjoc.9.228

Cited by 5 publications

(1 citation statement)

References 23 publications

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“…However, the stereostructure of 1 has not been elucidated yet because of its complicated molecular structure characterized by 61 stereocenters and molecular weight of 2860. Therefore, we are now examining the degradation of natural symbiodinolide ( 1 ) , and chemical synthesis of each fragment including the stereoisomers toward the complete stereochemical establishment of 1 . Previously, as a degradation of symbiodinolide ( 1 ), we carried out the methanolysis and subsequent oxidative cleavage with Grubbs II catalyst/NaClO to yield the C1–C13 fragment 2 (Scheme ). , Herein, as a part of our efforts toward the complete configurational determination of symbiodinolide ( 1 ), we describe the stereostructural analysis of the degraded product 2 , and stereodivergent and stereoselective synthesis of all four possible diastereomers of the C1–C13 fragment 2 , which has established the relative stereostructure of this fragment.…”

Section: Introductionmentioning

confidence: 99%

Stereodivergent Synthesis and Relative Stereostructure of the C1–C13 Fragment of Symbiodinolide

et al. 2015

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Four possible diastereomers of the C1-C13 fragment of symbiodinolide, which were proposed by the stereostructural analysis of the degraded product, were synthesized in a stereodivergent and stereoselective manner. The key transformations were aldol reaction of methyl acetoacetate with the aldehyde, diastereoselective reduction of the resulting β-hydroxy ketone, and the stereoinversion at the C6 position. Comparison of the (1)H NMR data between the four synthetic products and the degraded product revealed the relative stereostructure of the C1-C13 fragment of symbiodinolide.

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Section: Introductionmentioning

confidence: 99%

Stereodivergent Synthesis and Relative Stereostructure of the C1–C13 Fragment of Symbiodinolide

et al. 2015

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The J ulia– K ocienski Olefination

Blakemore¹,

Sephton

Ciganek

2018

Organic Reactions

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The Julia–Kocienski olefination is a direct connective synthesis of alkenes via the addition of metalated aryl alkyl sulfones to carbonyl compounds. The activating aromatic group associated with the sulfone must possess electrophilic character, and alkene formation occurs via β‐alkoxy sulfone formation, transfer of the aryl group from sulfur to oxygen via a Smiles rearrangement, and then elimination of sulfur dioxide and an aryloxide anion from the resulting β‐aryloxy sulfinate anion. The olefination process itself and the methods used to prepare the requisite sulfone substrates are tolerant of a wide variety of functional groups, and a variety of alkene targets can be prepared. Stereoselectivity is dependent on the nature of the sulfone, the carbonyl compound, the activating aryl moiety, and the reaction conditions. This chapter describes theoretical and operational aspects of the Julia–Kocienski olefination such that the reader will be able to obtain optimal results in his/her own research. A detailed mechanistic overview is included to account for the factors that influence stereoselectivity and yield. Methods for introducing sulfone activators into fragments of interest, best practices for generating sulfone anions, and optimal strategies for targeting different classes of alkene targets are discussed. Functional group compatibilities, reaction variants, and a comparison to other methods of alkene synthesis are also presented. Tabular surveys are organized according to type of alkene synthesized, with an emphasis on the degree of substitution and the level of conjugation about the newly formed double bond. The literature is covered from the initial disclosure of the Julia–Kocienski olefination in 1991 to the first quarter of 2016.

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Stereoselective Synthesis of the Proposed C79–C104 Fragment of Symbiodinolide

Takamura

Fujiwara

Kawakubo

et al. 2015

Chemistry A European J

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Stereoselective and streamlined synthesis of the proposed C79-C104 fragment 2 of symbiodinolide (1), a polyol marine natural product with a molecular weight of 2860, was achieved. In the synthetic route, the proposed C79-C104 fragment 2 was synthesized by utilizing a Julia-Kocienski olefination and subsequent Sharpless asymmetric dihydroxylation as key transformations in a convergent manner. Detailed comparison of the C NMR chemical shifts between the natural product and the synthetic C79-C104 fragment 2 revealed that the stereostructure at the C91-C99 carbon chain moiety of symbiodinolide (1) should be reinvestigated.

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Stereoselective synthesis of the C79–C97 fragment of symbiodinolide

Cited by 5 publications

References 23 publications

Stereodivergent Synthesis and Relative Stereostructure of the C1–C13 Fragment of Symbiodinolide

Stereodivergent Synthesis and Relative Stereostructure of the C1–C13 Fragment of Symbiodinolide

The J ulia– K ocienski Olefination

Stereoselective Synthesis of the Proposed C79–C104 Fragment of Symbiodinolide

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