Novel and Versatile Photosensitized Oxygenation Reaction of &amp;alpha;-Cedrene

Wu, Wenfeng; An, Feng; Geng, Zhengsong; Jiang, Zhichao

doi:10.2174/1570178611310030015

Cited by 2 publications

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“…As outlined in the retrosynthetic analysis for the stereoselective preparation of cis- 3 in Scheme , we started our studies with the evaluation of synthetic routes toward allyl alcohol 6 (Scheme ). Zhang and co-workers reported photocatalyzed oxidation of cedrene ( 1 ) to 6 using molecular oxygen as the oxidant . In our hands, the reaction showed insufficient conversion under the reported conditions, which might be due to differences in the reaction set up.…”

Section: Resultsmentioning

confidence: 57%

“…Zhang and co-workers reported photocatalyzed oxidation of cedrene (1) to 6 using molecular oxygen as the oxidant. 14 In our hands, the reaction showed insufficient conversion under the reported conditions, which might be due to differences in the reaction set up. After reduction of the hydroperoxide with triphenylphosphane, compound 6 was isolated in 43% yield.…”

Section: ■ Results and Discussionmentioning

confidence: 62%

“…β-Cedren-9-ol (6). 14 Under an argon atmosphere, diisopropylamine (6.40 mL, 4.61 g, 45.5 mmol) was dissolved in anhydrous THF (20 mL) and cooled to 0 °C. n-BuLi (18.2 mL, 2.5 M in hexane, 45.5 mmol) was added dropwise.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…The formation of cedralon (4) from 2 under acidic conditions has been reported previously. 14,15 Subsequent acetalization of the diol mixture using acetone gives the corresponding acetonide 5 as a mixture of diastereomers that contains cis-5a, in which the dioxolane ring is orientated exo with respect to the methylene bridge, as the major component. The moderate yield of 45% in this step can be attributed to the formation of by-products, e.g., due to elimination in the conversion of acid-sensitive diol 3 with acetone under acidic reaction conditions.…”

Section: ■ Introductionmentioning

confidence: 99%

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Stereoselective Synthesis of acis-Cedrane-8,9-diol as a Key Intermediate for an Amber Odorant

Stefanow

Grandane

et al. 2020

Org. Process Res. Dev.

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The naturally occurring (−)-α-cedrene exhibits a weak woody and cedarlike odor. In contrast, cis-cedrene acetonide, which is a derivative of cedrene, is an extremely powerful semisynthetic aroma molecule. The current process starting from cedrene yields cis-cedrene acetonide in an overall yield of <20%. Herein, we report two synthetic pathways toward this valuable product starting either by isomerization of commercially available cedrene epoxide or by photo-oxidation of (−)-α-cedrene to an allylic intermediate. The key step of the synthesis is the epoxidation of the protected or even unprotected allyl alcohol followed by the reductive opening of the epoxide. This reaction sequence leads to the respective cis-diol with the correct stereochemistry. Subsequent acetalization gives cis-cedrene acetonide in up to 78% overall yield. We also report our attempt to prepare the cis-diol with inverted stereochemistry. In this context, we inverted the configuration of the allylic alcohol via a Mitsunobu reaction. However, only the acetyl-protected alcohol could be epoxidized, leading the undesired trans-product in >99% yield.

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Section: Resultsmentioning

confidence: 57%

Section: ■ Results and Discussionmentioning

confidence: 62%

Section: ■ Experimental Sectionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Stereoselective Synthesis of acis-Cedrane-8,9-diol as a Key Intermediate for an Amber Odorant

Stefanow

Grandane

et al. 2020

Org. Process Res. Dev.

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Synthesis of 1,2‐Dioxetanes as Thermochemiluminescent Labels for Ultrasensitive Bioassays: Rational Prediction of Olefin Photooxygenation Outcome by Using a Chemometric Approach

Andronico

Quintavalla

Lombardo

et al. 2016

Chemistry A European J

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Great interest in new thermochemiluminescent (TCL) molecules, for example, in bioanalytical assays, has prompted the design and synthesis of a small library of more than 30 olefins to be subjected to photooxygenation, with the aim of obtaining new 1,2-dioxetane-based TCL labels with optimized properties. Fluorine atoms on the acridan system remarkably stabilize 1,2-dioxetanes when they are located in the 3- and/or 6-position (4 h and 4 i). On the other hand, 2,7-difluorinated acridan dioxetane (4 j) showed a significantly enhanced fluorescence quantum yield with respect to the unsubstituted dioxetane (4 a). Some of the synthesized olefins did not undergo singlet oxygen addition and a rationale was sought to ease the photooxygenation step, leading to the TCL dioxetanes. A chemometric approach has been adopted to exploit principal component analysis and linear discriminant analysis of the structural and electronic molecular descriptors obtained by DFT optimizations of olefins 3. This approach allows the steric and electronic parameters that govern dioxetane formation to be revealed.

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Novel and Versatile Photosensitized Oxygenation Reaction of α-Cedrene

Cited by 2 publications

References 0 publications

Stereoselective Synthesis of acis-Cedrane-8,9-diol as a Key Intermediate for an Amber Odorant

Stereoselective Synthesis of acis-Cedrane-8,9-diol as a Key Intermediate for an Amber Odorant

Synthesis of 1,2‐Dioxetanes as Thermochemiluminescent Labels for Ultrasensitive Bioassays: Rational Prediction of Olefin Photooxygenation Outcome by Using a Chemometric Approach

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