Enantioselective synthesis of the C5–C23 segment of biselyngbyaside

Chandrasekhar, Srivari; Rajesh, G.; Naresh, Tumma

doi:10.1016/j.tetlet.2012.11.015

Cited by 19 publications

(12 citation statements)

References 33 publications

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“…Our route to C14–C23 fragment 9 addresses the branched/linear problems experienced Chandrasekhar 10a and Goswami, 7 as well as the problems of Z / E mixtures faced by Suenaga. 5,6 We have also shown that catalytic conditions can be used to generate the C17 stereocenter.…”

Section: Resultsmentioning

confidence: 99%

“…Owing to their interesting biological activity, these compounds have drawn the attention of the synthetic community. Completed syntheses of biselyngbyolide A, 5 biselyngbyolide B, 6,7,8 and biselyngbyaside 9 have already appeared in the literature, 10 but most suffer from deficiencies on a number of fronts. Many involve numerous protecting group manipulations and oxidation state changes that drive up the step count.…”

Section: Introductionmentioning

confidence: 99%

“…Previous attempts at forming the C19–C20 bond are summarized in Scheme 1. Most suffer from either poor regioselectivity 7,10a ( A vs. B and C vs. D ) or poor control of Z / E selectivity. 5,6 These problems are exacerbated by the fact that these product mixtures must be carried through several steps before the isomers can be separated.…”

Section: Introductionmentioning

confidence: 99%

“…In addition to identifying conditions for a more efficient construction of the C19–C20 bond, it would also be b eneficial if formation of the C17 stereocenter could be achieved using catalyst control. Existing routes rely on a commercial source that must then heavily modified for this application, 5,6 or use a chiral reagent 7,8 or auxiliary 10a to introduce asymmetry. Herein we report our efforts on both of these fronts.…”

Section: Introductionmentioning

confidence: 99%

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Stereoselective synthesis of the C14 C23 fragment of biselyngbyolide A and B enabled by transition metal catalysis

et al. 2018

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Transition met al catalysis has enabled the highly stereoselective and protecting group-free synthesis of the C14–C23 fragment of the apoptosis-inducing natural products biselyngbyolide A and B. A Pd-catalyzed Stille reaction between a vinyl stannane and a crotyl carbonate formed the skipped diene with complete control of the the trisubstituted bond and excellent control over the branched/linear products. A Cu-catalyzed Stahl oxidation was used to form the requisite aldehyde needed for a Ag-catalyzed asymmetric allylation. The latter provided the final fragment with excellent stereochemical control.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Stereoselective synthesis of the C14 C23 fragment of biselyngbyolide A and B enabled by transition metal catalysis

et al. 2018

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“…collected from Okinawa Prefecture, Japan. Biselyngbyaside ( 17 ) shows a broad spectrum of cytotoxicity against human solid tumor cell lines, especially for HeLa S 3 cells with an IC 50 value of 0.1 μg/mL [ 15 ], and its total synthesis was completed [ 35 ]. Extensive efforts toward finding cytotoxic natural products have resulted in the isolation of three analogs of biselyngbyaside ( 17 ), named biselyngbyasides B–D ( 18 – 20 ), from the marine cyanobacterium Lyngbya sp.…”

Section: Anti-neoplastic Property Of Cyanobacterium-derived Macrolmentioning

confidence: 99%

A Review Study on Macrolides Isolated from Cyanobacteria

Wang

Zhang

et al. 2017

Marine Drugs

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Cyanobacteria are rich sources of structurally-diverse molecules with promising pharmacological activities. Marine cyanobacteria have been proven to be true producers of some significant bioactive metabolites from marine invertebrates. Macrolides are a class of bioactive compounds isolated from marine organisms, including marine microorganisms in particular. The structural characteristics of macrolides from cyanobacteria mainly manifest in the diversity of carbon skeletons, complexes of chlorinated thiazole-containing molecules and complex spatial configuration. In the present work, we systematically reviewed the structures and pharmacological activities of macrolides from cyanobacteria. Our data would help establish an effective support system for the discovery and development of cyanobacterium-derived macrolides.

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TheJulia–Kocienski 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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Enantioselective synthesis of the C5–C23 segment of biselyngbyaside

Cited by 19 publications

References 33 publications

Stereoselective synthesis of the C14 C23 fragment of biselyngbyolide A and B enabled by transition metal catalysis

Stereoselective synthesis of the C14 C23 fragment of biselyngbyolide A and B enabled by transition metal catalysis

A Review Study on Macrolides Isolated from Cyanobacteria

TheJulia–Kocienski Olefination

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