Total Synthesis of (−)-Apicularen A

Su, Qibin; Panek, James S.

doi:10.1021/ja037957x

Cited by 129 publications

(38 citation statements)

References 26 publications

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“…[17] Condensing aldehyde 18 with allylsilane 19, the methyl ether analog of 11, in the presence of TMSOTf led to a Prins-type cyclization through boat methyl monate C (Scheme 9), [19] an analog of the antibiotic pseudomonic acid C. This reaction proceeds through the BF 3 ·OEt 2 -mediated condensation of acetal 22 with alcohol 23. Employing protecting groups for the oxygen atom that are less electron-withdrawing causes erosion or inversion of the stereoselectivity for the reaction, because electrostatic interactions between that oxygen atom and the oxocarbenium ion can promote a boat transition state.…”

Section: Electron-rich Alkene Nucleophilesmentioning

confidence: 99%

Prins‐Type Cyclization Reactions in Natural Product Synthesis

2013

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Prins‐type cyclization reactions proceed through the intramolecular addition of a π‐nucleophile to an oxocarbenium ion or related species to generate a ring through carbon–carbon bond formation, often with excellent and predictable stereocontrol. The widespread presence of naturally occurring oxygen‐containing heterocycles has made these reactions exceedingly valuable for total synthesis efforts. This microreview covers several common variations of Prins‐type cyclizations and highlights their applicability to the total synthesis of natural products and analogs.

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Section: Electron-rich Alkene Nucleophilesmentioning

confidence: 99%

Prins‐Type Cyclization Reactions in Natural Product Synthesis

2013

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“…Thus, the acid-mediated condensation of chiral syn-allylsilyl ethers with aryl, benzyl or vinyl aldehydes selectively provides cis-2,6-disubstituted dihydropyrans. [14] These results suggest chair-like transition states with C-2 and C-6 substituents pseudoequatorial and the silyl group in a pseudoaxial orientation, to allow the needed perpendicular alignment of the C-Si and the C=C double bond for effective hyperconjugative stabilization (Scheme 8). Under the same conditions, chiral syn-(E)-crotylsilyl ethers give cis-2,6-trans-5,6-trisubstituted dihydropyrans [15] as the major isomers, through an analogous chair-like type of transition state (Scheme 9).…”

Section: Synthesis Of Dihydropyrans and Tetrahydropyransmentioning

confidence: 92%

“…Panek proposed an efficient methodology for the synthesis of polysubstituted dihydropyrans from allylsilyl alcohols, in which the stereochemical arrangement of the silyl and the hydroxy or ether groups on the starting allylsilane determines the configuration of C‐2 and C‐6 on the final tetrahydropyran. Thus, the acid‐mediated condensation of chiral syn ‐allylsilyl ethers with aryl, benzyl or vinyl aldehydes selectively provides cis ‐2,6‐disubstituted dihydropyrans . These results suggest chair‐like transition states with C‐2 and C‐6 substituents pseudoequatorial and the silyl group in a pseudoaxial orientation, to allow the needed perpendicular alignment of the C–Si and the C=C double bond for effective hyperconjugative stabilization (Scheme ).…”

Section: Synthesis Of Oxacycles By Silyl‐prins Cyclizationmentioning

confidence: 98%

Synthesis of O‐ and N‐Heterocycles by Silyl‐Prins Cyclization of Allylsilanes

Díez-Poza

Barbero

2017

Eur J Org Chem

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Prins cyclization has emerged as one of the most valuable methods for the construction of heterocycles. It proceeds through intramolecular addition of a π‐nucleophile to an oxocarbenium or related ion. The use of electron‐rich alkenes, such as allylsilanes (so‐called silyl‐Prins cyclization) offers the benefit of allowing more selective reactions. The regio‐ and stereochemical outcomes of these transformations are explained by well‐stablished transition states. This review presents the most important contributions involving silyl‐Prins cyclization to the stereoselective preparation of oxygen and nitrogen heterocycles. The influence of different structural variants in the selectivity of the cyclization is discussed. These reactions have frequently been used as key steps in the synthesis of a wide variety of natural products.

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“…30, 31 The reaction displays high diastereoselectivity showing the relative configuration (2,6- cis or 2,6- trans ), strongly dependent on the nature of the R 2 substituent. Panek and collaborators also proposed a stereoselective annulation employing anti -allylsilanes to provide cis -dihydropyran rings.…”

Section: Introductionmentioning

confidence: 99%

Achmatowicz reaction and its application in the syntheses of bioactive molecules

Ghosh

Brindisi

2016

RSC Adv.

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Substituted pyranones and tetrahydropyrans are structural subunits of many bioactive natural products. Considerable efforts are devoted toward the chemical synthesis of these natural products due to their therapeutic potential as well as low natural abundance. These embedded pyranones and tetrahydropyran structural motifs have been the subject of synthetic interest over the years. While there are methods available for the syntheses of these subunits, there are issues related to regio and stereochemical outcomes, as well as versatility and compatibility of reaction conditions and functional group tolerance. The Achmatowicz reaction, an oxidative ring enlargement of furyl alcohol, was developed in the 1970s. The reaction provides a unique entry to a variety of pyranone derivatives from functionalized furanyl alcohols. These pyranones provide convenient access to substituted tetrahydropyran derivatives. This review outlines general approaches to the synthesis of tetrahydropyrans, covering general mechanistic aspects of the Achmatowicz reaction or rearrangement with an overview of the reagents utilized for the Achmatowicz reaction. The review then focuses on the synthesis of functionalized tetrahydropyrans and pyranones and their applications in the synthesis of natural products and medicinal agents.

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Total Synthesis of (−)-Apicularen A

Cited by 129 publications

References 26 publications

Prins‐Type Cyclization Reactions in Natural Product Synthesis

Prins‐Type Cyclization Reactions in Natural Product Synthesis

Synthesis of O‐ and N‐Heterocycles by Silyl‐Prins Cyclization of Allylsilanes

Achmatowicz reaction and its application in the syntheses of bioactive molecules

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