DIBUTYL ACETYLENEBORONATE<sup>1</sup>

Matteson, Donald S.; Peacock, Kenneth

doi:10.1021/ja01506a056

Cited by 29 publications

(10 citation statements)

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“…[23] For example, vinylboronic acid is highly unstable and cannot be isolated; [24] its solution. As mentioned above, the products were found to be extremely stable compounds, both in the solid state and in ing organoboronic acids or esters.…”

Section: Preparation Of Potassium Organotrifluoroboratesmentioning

confidence: 99%

Potassium Organotrifluoroborates: New Partners in Palladium-Catalysed Cross-Coupling Reactions

Darses¹,

Michaud²,

Genêt³

1999

Eur. J. Org. Chem.

152

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Section: Preparation Of Potassium Organotrifluoroboratesmentioning

confidence: 99%

Potassium Organotrifluoroborates: New Partners in Palladium-Catalysed Cross-Coupling Reactions

Darses¹,

Michaud²,

Genêt³

1999

Eur. J. Org. Chem.

152

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“…We discovered that ( E )‐ 1 and ( Z )‐ 1 can both be generated from the novel ethynyl MIDA boronate 6 , which in turn can be prepared from readily available Grignard reagent 5 2h. 9 Specifically, as shown in Scheme , the addition of 5 to trimethyl borate followed by direct transligation of the resulting magnesium ate complex with MIDA generated 6 as a colorless, crystalline solid. When this transligation was executed at 115 °C,2f a very good yield of 6 was achieved on the decagram scale.…”

Section: Methodsmentioning

confidence: 99%

A Simple and General Platform for Generating Stereochemically Complex Polyene Frameworks by Iterative Cross‐Coupling

2010

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Aiming to maximally harness the inherent modularity of small molecules, we are pursuing the development of a synthesis strategy based on the iterative cross-coupling (ICC) of bifunctional building blocks representing the substructures that most commonly appear in natural products. [1, 2] In this vein, various combinations of trans-and cis-olefins are found in many small molecules derived from a wide range of biosynthetic pathways, including polyketides, hybrid peptide/ polyketides, polyterpines, and fatty acids (Scheme 1). [3,4] Enabling stereospecific access to these stereochemically complex polyene frameworks, we herein describe the development of a novel ICC platform that yields bifunctional iodopolyenyl N-methyliminodiacetic acid (MIDA) boronates in all possible stereoisomeric forms. The power of this approach has been realized in the first synthesis of the highly complex (E,E,E,Z,Z,E,E)-heptaene framework of the ion channel-forming polyene macrolide vacidin A.We recently reported three haloalkenyl MIDA boronates that enabled the preparation of a subset of polyene motifs by ICC.[2b] Albeit an important step forward, this collection only provided access to all-trans-polyene substructures and utilized polyenylchlorides. Accessing stereochemically complex polyene motifs is substantially more challenging because, in addition to the sensitivities observed with all polyenes to light, oxygen, and acid, frameworks containing cis double bonds can isomerize to the typically more thermodynamically stable all-trans structures. Moreover, poorly reactive polyenylchlorides proved to be minimally effective in complex applications.To overcome both of these limitations, we pursued a novel strategy for making iodopolyenyl MIDA boronates by ICC of iodide-masked [5] bifunctional building blocks. As shown in Scheme 2 A, the approach involves metal-selective crosscoupling of Sn/Ge bis-metalated olefins [6] to generate polyenylgermanium intermediates followed by stereospecific iododegermylations. [7] To the best of our knowledge, iododegermylations of polyenylgermanium species were unreported. However, the facility of halodegermylation [7] vs. halodesilylation [8] of simple olefins suggested that the former process had superior potential to be efficient and stereoretentive in the context of structurally and stereochemically complex polyene systems. Guided by this logic, we hypothesized that iterative cycles of metal-selective coupling/iododegermylation with core building blocks 1 and 2 (Scheme 2 B) could Scheme 1. Polyene natural products derived from a wide range of biosynthetic pathways. Scheme 2. A) A strategy for ICC of halogen-masked bifunctional building blocks. B) Core building blocks to enable general access to stereoisomeric iodopolyenyl MIDA boronates. C) New iodopolyenyl MIDA boronates for the synthesis of polyene natural products.

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“…Thin layer chromatography (TLC) was performed on aluminium-backed plates pre-coated with silica (0.2 mm, Merck DC-alufolien Kieselgel 60 F254), which were developed using standard visualizing agents: ultraviolet light or potassium permanganate. 1 H-NMR spectra were recorded on a Bruker AV-250 (250 MHz) and AV-400 (400 MHz). Chemical shifts are reported in ppm with the solvent resonance as the internal standard (CHCl3: δ 7.26 ppm).…”

Section: General Remarksmentioning

confidence: 99%

“…Since their discovery by Matteson in 1960 [1], alkynylboronates have proven to be a versatile and popular class of synthetic intermediates in organic synthesis. They combine the traditional nucleophilic properties of alkyne-based organometallics and, as such, undergo metal catalysed cross-coupling [2][3][4], as well as addition to aldehydes and imines [5].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterisation and Reactions of Phosphine-Substituted Alkynylboronates and Alkynyltrifluoroborate Salts

et al. 2014

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Abstract:The synthesis and structural characterisation of phosphine-substituted alkynylboronates is reported. A P(III)-centred alkynylboronate (2) was prepared that showed little evidence for the conjugation of the P-lone pair to the boron via the alkyne π-system, as judged by X-ray crystallography studies of 2 and a related P(V) compound, 3. In addition, corresponding alkynyltrifluoroborate salts were prepared that showed improved stability by comparison to their boronic ester counterparts. These salts undergo Pd-catalysed cross-coupling reactions with aryl halides.

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DIBUTYL ACETYLENEBORONATE¹

Cited by 29 publications

References 0 publications

Potassium Organotrifluoroborates: New Partners in Palladium-Catalysed Cross-Coupling Reactions

Potassium Organotrifluoroborates: New Partners in Palladium-Catalysed Cross-Coupling Reactions

A Simple and General Platform for Generating Stereochemically Complex Polyene Frameworks by Iterative Cross‐Coupling

Synthesis, Characterisation and Reactions of Phosphine-Substituted Alkynylboronates and Alkynyltrifluoroborate Salts

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DIBUTYL ACETYLENEBORONATE1

Cited by 29 publications

References 0 publications

Potassium Organotrifluoroborates: New Partners in Palladium-Catalysed Cross-Coupling Reactions

Potassium Organotrifluoroborates: New Partners in Palladium-Catalysed Cross-Coupling Reactions

A Simple and General Platform for Generating Stereochemically Complex Polyene Frameworks by Iterative Cross‐Coupling

Synthesis, Characterisation and Reactions of Phosphine-Substituted Alkynylboronates and Alkynyltrifluoroborate Salts

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DIBUTYL ACETYLENEBORONATE¹