Total Synthesis of (±)-Taxusin

Hara, Ryujiro; Furukawa, Takashi; Horiguchi, Yoshiaki; Kuwajima, Isao

doi:10.1021/ja9610949

Cited by 52 publications

(41 citation statements)

References 17 publications

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“…Not surprisingly, their unusual structural/chemical properties and interesting bonding characteristics have attracted the attention of physical organic chemists . Despite their strained structures and high reactivity, cyclopropanes are usually quite stable at room temperature, and are present in a variety of natural and unnatural products including pheromones, terpenes, fatty acid metabolites and epothilone analogs …”

Section: Introductionmentioning

confidence: 99%

“…[6] Despite their strained structures and high reactivity, cyclopropanes are usually quite stable at room temperature, and are present in a variety of natural and unnatural products including pheromones, terpenes, fatty acid metabolites and epothilone analogs. [1][2][3][7][8][9][10] In recent years, a growing interest in enantioenriched cyclopropanes has stirred the development of their asymmetric synthesis. [11] The Simmons-Smith cyclopropanation has been frequently employed in the stereoselective cyclopropanation of olefins and allylic alcohols with chiral auxiliaries or with stoichiometric additives, and excellent stereoselectivities have been reported.…”

Section: Introductionmentioning

confidence: 99%

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Tandem catalytic enantio‐ and diastereoselective synthesis of cyclopropyl alcohols using aryl aldehydes

Kim

Walsh

2012

J of Physical Organic Chem

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The prevalence of cyclopropanes in biologically active compounds has fueled many investigations into their preparation. Despite significant advances, more efficient methods for their catalytic enantioselective synthesis remain in demand. Previously, we reported a novel tandem approach to diastereo‐ and enantioenriched cyclopropyl alcohols. Our method involved an initial asymmetric C–C bond formation by addition of organozinc reagents to aldehydes catalyzed by a (−)‐MIB‐based catalyst. The resulting allylic zinc alkoxides were then subject to directed cyclopropanations. Although this approach provided cyclopropyl alcohols with very high enantio‐ and diastereoselectivity, it was successful with only aliphatic aldehydes. Aryl aldehyde substrates, on the other hand, exhibited low conversion and variable diastereomeric ratios. The present study is aimed at raising the stereoselectivity and yield of the aforementioned tandem reaction with aryl aldehyde substrates to make the method synthetically useful. Herein, we report the successful optimization of aryl aldehyde substrates in our one‐pot tandem approach leading to cyclopropyl alcohols with high yields and enantio‐ and diastereoselectivities. Copyright © 2012 John Wiley & Sons, Ltd.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tandem catalytic enantio‐ and diastereoselective synthesis of cyclopropyl alcohols using aryl aldehydes

Kim

Walsh

2012

J of Physical Organic Chem

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“…4 Recently, several other natural taxanes such as taxinine and taxuspines were also revealed to exhibit multi-drug resistancereversing activity. After our achievement of the second synthesis as a racemic form, 7 Paquette et al have recently described the third total synthesis as the natural (+)-form starting from D-camphor. At the end of this century, total synthesis of taxusin has been reported by three groups.…”

Section: Introductionmentioning

confidence: 99%

Synthetic Studies on Taxoids: Enantioselective Total Synthesis of (+)-Taxusin and (-)-Taxol

2000

Synlett

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To construct taxane ABC tricarbocycles, a useful methodology including an aldol-like eight-membered B ring cyclization between dienol silyl ethers and acetals was explored. By applying this methodology, the enantioselective total syntheses of (+)-taxusin and (-) -taxol have been achieved, starting from the substrate containing a chiral center at each C1 site, based on AC to ABC strategies. Syntheses of several artificial taxoids are also described. Conclusion

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“…As illustrated in Figure 1, Taxol can be viewed as a "level 11" taxane because of the presence of nine oxidized carbon atoms and two degrees of unsaturation; over 100 natural products at this oxidation state have been isolated. Similarly, decinnamoyltaxinine E (2), [29] taxabaccatin III (3), [30] taxusin (4), [31][32][33][34][35][36] taxuyunnanine D (5), [37,38] and taxadiene (6) [39][40][41] can be viewed as level 2-7 taxanes and represent over 100 additional natural products. In this report, the first enantioselective total syntheses of 2 and 3 are presented.…”

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confidence: 99%

“…In the case of the taxanes,o fw hich hundreds are known, [28] this approach simplifies the retrosynthetic blueprint as family members can be simply abbreviated as mathematical sets rather than discreet targets.A si llustrated in Figure 1, Taxol can be viewed as a"level 11" taxane because of the presence of nine oxidized carbon atoms and two degrees of unsaturation;o ver 100 natural products at this oxidation state have been isolated. Similarly,d ecinnamoyltaxinine E( 2), [29] taxabaccatin III (3), [30] taxusin (4), [31][32][33][34][35][36] taxuyunnanine D(5), [37,38] and taxadiene (6) [39][40][41] can be viewed as level 2-7 taxanes and represent over 100 additional natural products.Inthis report, the first enantioselective total syntheses of 2 and 3 are presented. As the most advanced embodiment of two-phase chemical synthesis to date,t his route builds highly complex taxanes containing five oxidized carbon atoms and two degrees of unsaturation in only 18 steps from as imple olefin feedstock (tetramethylethylene; 8).…”

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confidence: 99%

Short, Enantioselective Total Synthesis of Highly Oxidized Taxanes

et al. 2016

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In the realm of natural product chemistry, few isolates have risen to the level of fame justifiably accorded to Taxol (1) and its chemical siblings. This report describes the most concise route to date for accessing the highly oxidized members of this family. As representative members of taxanes containing five oxygen atoms, decinnamoyltaxinine E (2) and taxabaccatin III (3), have succumbed to enantioselective total synthesis for the first time in only 18 steps from a simple olefin starting material. The strategy holistically mimics natures approach (two-phase synthesis) and features a carefully choreographed sequence of stereoselective oxidations and a remarkable redox-isomerization to set the key trans-diol present in 2 and 3. This work lays the critical groundwork necessary to access even higher oxidized taxanes such as 1 in a more practical fashion, thus empowering a medicinal chemistry campaign that is not wedded to semi-synthesis.[ + ] These authors contributed equally.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under http://dx.

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Total Synthesis of (±)-Taxusin

Cited by 52 publications

References 17 publications

Tandem catalytic enantio‐ and diastereoselective synthesis of cyclopropyl alcohols using aryl aldehydes

Tandem catalytic enantio‐ and diastereoselective synthesis of cyclopropyl alcohols using aryl aldehydes

Synthetic Studies on Taxoids: Enantioselective Total Synthesis of (+)-Taxusin and (-)-Taxol

Short, Enantioselective Total Synthesis of Highly Oxidized Taxanes

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