Total Synthesis of Synechoxanthin through Iterative Cross‐Coupling

Fujii, Seiko; Chang, Stephanie Y.; Burke, Martin D.

doi:10.1002/ange.201102688

Cited by 31 publications

(6 citation statements)

References 41 publications

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“…Syntheses of many of these building blocks can further be facilitated using already commercially available MIDA boronates, including BB1-BB4 , just as the capping element 18 in the synthesis of asnipyrone B was prepared in a single step from BB3 . Finally, alkenyl MIDA boronates can be converted directly into alkenyl halides, 27 allowing for rapid preparation of many halide capping elements from the corresponding readily accessible MIDA boronates.…”

Section: Discussionmentioning

confidence: 99%

Synthesis of most polyene natural product motifs using just 12 building blocks and one coupling reaction

2014

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The inherent modularity of polypeptides, oligonucleotides, and oligosaccharides has been harnessed to achieve generalized building block-based synthesis platforms. Importantly, like these other targets, most small molecule natural products are biosynthesized via iterative coupling of bifunctional building blocks. This suggests that many small molecules also possess inherent modularity commensurate with systematic building block-based construction. Supporting this hypothesis, here we report that the polyene motifs found in >75% of all known polyene natural products can be synthesized using just 12 building blocks and one coupling reaction. Using the same general retrosynthetic algorithm and reaction conditions, this platform enabled the synthesis of a wide range of polyene frameworks covering all of this natural product chemical space, and first total syntheses of the polyene natural products asnipyrone B, physarigin A, and neurosporaxanthin β-D-glucopyranoside. Collectively, these results suggest the potential for a more generalized approach for making small molecules in the laboratory.

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Section: Discussionmentioning

confidence: 99%

Synthesis of most polyene natural product motifs using just 12 building blocks and one coupling reaction

2014

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“…Boron‐protecting methods through diminution of the Lewis acidity of a boron center has opened up a new vista of modern organoboron chemistry,1, 2 because it enables precise control of the reactivity of organoboron compounds, which leads to iterative Suzuki–Miyaura cross‐coupling for synthesizing complex natural products,1a–c, h, k, n oligoarenes2a–d, f and so on via B‐masking/unmasking processes. One of the most commonly used protecting groups for this purpose is 1,8‐diaminonaphthalene (dan),2 and B‐protected organoboron compounds of the form RB(dan) have been conventionally prepared by condensation of the respective boronic acids with dan 2a.…”

Section: Introductionmentioning

confidence: 99%

Direct Synthesis of Boron‐Protected Alkenyl‐ and Alkylborons via Copper‐Catalyzed Formal Hydroboration of Alkynes and Alkenes

2014

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Formal hydroboration of internal alkynes proceeds regio‐ and stereoselectively by the use of a diboron reagent masked with 1,8‐diaminonaphthalene (dan) in the presence of readily available [(Ph3P)3CuCl], leading to direct formation of diverse B‐protected alkenylborons in high yield. The B(dan) moiety can also be efficiently installed into the CC double bond of alkenes to afford the respective alkylborons.

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“…This new synthetic route illustrates the unmatched potential of the metal‐catalyzed cross‐coupling processes as efficient tools for the synthesis of complex polyenes. These processes take place preferentially with retention of configuration of the coupling partners, and in the case of difunctionalized substrates positional selectivity can be achieved, which allows the use of iterative cross‐coupling sequences in the synthetic scheme 11–13. In the case of pyrrhoxanthin, the non‐symmetrical C 8 ‐dibromide and the C 7 ‐bis‐metallated linchpins, 6 and 5 , reacted preferentially at the most electron‐deficient and at the least‐hindered positions, respectively.…”

Section: Introductionmentioning

confidence: 99%

Total Synthesis of Enantiopure Pyrrhoxanthin: Alternative Methods for the Stereoselective Preparation of 4‐Alkylidenebutenolides

Vaz

Otero

Álvarez

et al. 2013

Chemistry A European J

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A new stereocontrolled total synthesis of the configurationally labile C37 -norcarotenoid pyrrhoxanthin in enantiopure form has been completed. A highly stereoselective Horner-Wadsworth-Emmons (HWE) condensation of a C17-allylphosphonate and a C20-aldehyde was used as the last conjunctive step. Both a Sonogashira reaction to form the C17-phosphonate and the final HWE condensation proved to be compatible with the sensitive C7-C10 enyne E configuration. Regioselective (5-exo-dig) silver-promoted lactonization reactions of three alternative pent-2-en-4-ynoic acid precursors with increased complexity, including a fully functionalized C20-fragment, were explored for the preparation of the γ-alkylidenebutenolide fragment. This survey extends the existing methodologies for the preparation of oxygen-containing carotenoids (xanthophylls) and streamlines the synthesis of additional members of the C37-norcarotenoid butenolide family of natural products.

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Total Synthesis of Synechoxanthin through Iterative Cross‐Coupling

Cited by 31 publications

References 41 publications

Synthesis of most polyene natural product motifs using just 12 building blocks and one coupling reaction

Synthesis of most polyene natural product motifs using just 12 building blocks and one coupling reaction

Direct Synthesis of Boron‐Protected Alkenyl‐ and Alkylborons via Copper‐Catalyzed Formal Hydroboration of Alkynes and Alkenes

Total Synthesis of Enantiopure Pyrrhoxanthin: Alternative Methods for the Stereoselective Preparation of 4‐Alkylidenebutenolides

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