Development of silicon-tethered anionic reaction and its application to the synthesis of chiral A-ring moieties of Taxol™

Iwamoto, Mitsuhiro; Miyano, Masayuki; Utsugi, Masayuki; Kawada, Hatsuo; Nakada, Masahisa

doi:10.1016/j.tetlet.2004.09.143

Cited by 22 publications

(15 citation statements)

References 23 publications

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“…Due to steric hindrance, a high temperature was required, which resulted in chlorination to afford a mixture of bromomethylsilyl ether 20 and chloromethylsilyl ether 21 in moderate yields. After considerable investigation, we found that the chloromethylsilylation of 19 followed by Finkelstein iodination with NaI efficiently proceeded to afford iodomethylsilyl ether 22 in high yield …”

Section: Resultsmentioning

confidence: 94%

“…After considerable investigation, we found that the chloromethylsilylation of 19 followed by Finkelstein iodination with NaI efficiently proceeded to afford iodomethylsilyl ether 22 in high yield. 19 The cyclization of 22 was then examined (Table 1). The reaction using n Bu 3 SnH and AIBN afforded a mixture of the cyclized product 23 and uncyclized TMS ether 24 in moderate yields (entry 1).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Diastereoselective Methylation at the Congested β-Position of a Butenolide Ring: Studies toward the Synthesis of seco-Prezizaane-Type Sesquiterpenes

et al. 2019

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We established a method for installing a methyl group at the β-position of a butenolide ring. The methylated position is located at the congested ring juncture of a 5,6,5-tricyclic lactone, which is common to neurotrophic seco-prezizaane-type sesquiterpenes. The samarium(II)-mediated conjugate addition of the halomethylsilyl ethers tethered to the proximal hydroxy groups efficiently formed the desired C–C bond. Subsequent fluoride-free Tamao oxidation and Barton–McCombie deoxygenation converted the resultant cyclic silyl ether into the corresponding methyl group.

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Section: Resultsmentioning

confidence: 94%

Section: ■ Results and Discussionmentioning

confidence: 99%

Diastereoselective Methylation at the Congested β-Position of a Butenolide Ring: Studies toward the Synthesis of seco-Prezizaane-Type Sesquiterpenes

et al. 2019

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“…Following previous studies on intermolecular nucleophilic hydroxymethylation, Nakada et al . has developed silicon‐tethered intramolecular nucleophilic additions of a hydroxymethyl unit to ketones [55–56] . This method would be a promizing stereoselective generation of the chiral tertiary alcohol.…”

Section: Synthesismentioning

confidence: 99%

Design, Synthesis, and Evaluation of α‐(Hydroxymethyl)cycloalkanols

Nassar

Piva

2021

Eur J Org Chem

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α‐(Hydroxymethyl)cycloalkanols are pervasive structural scaffolds found in natural products and synthetic intermediates with varied biochemical and physicochemical properties. These profiles have driven numerous research groups to the synthesis of such motifs using innovative methodologies. The presence of vicinal diols attached to a cycloalkane makes from these motifs excellent synthetic intermediates for the synthesis of diverse ring systems. This investigation takes an overview of the literature for the occurrence and synthesis of α‐(hydroxymethyl)cycloalkanol derivatives, concentrating on advances in the last two decades.

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“…23 Moreover, compound 26 I (Scheme 6) was prepared from commercially available compounds in ve steps; 40 therefore, the number of synthetic steps required for the preparation of the A ring fragment 14 I was reduced to ten steps. However, the yield of the organocatalyzed α aminoxylation of 23 I with nitrosobenzene is unsatisfactory.…”

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confidence: 99%

Formal Total Synthesis of (−)-Taxol

Utsugi¹,

Iwamoto²,

Hirai³

et al. 2017

J. Synth. Org. Chem. Jpn.

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Formal total synthesis of ( ) taxol is described herein. This convergent synthesis was accomplished by utilizing two chiral fragments, both of which were prepared via asymmetric catalysis. A palladium catalyzed reaction was found to afford the eight membered ring effectively, i.e., a B alkyl Suzuki Miyaura coupling reaction and an intramolecular alkenylation of a methyl ketone successfully constructed the B ring of taxol in excellent yield. During the preparation of a substrate for the palladium catalyzed reaction, a unique rearrangement of the epoxy benzyl ether, via a 1,5 hydride shift that generates the C3 stereogenic center and subsequently forms the C1 C2 benzylidene moiety, was observed. Strenuous efforts were required for transformations after the construction of the taxane scaffold to achieve the formal total synthesis of taxol because very few approaches are available for the synthesis of the target compound.

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Development of silicon-tethered anionic reaction and its application to the synthesis of chiral A-ring moieties of Taxol™

Cited by 22 publications

References 23 publications

Diastereoselective Methylation at the Congested β-Position of a Butenolide Ring: Studies toward the Synthesis of seco-Prezizaane-Type Sesquiterpenes

Diastereoselective Methylation at the Congested β-Position of a Butenolide Ring: Studies toward the Synthesis of seco-Prezizaane-Type Sesquiterpenes

Design, Synthesis, and Evaluation of α‐(Hydroxymethyl)cycloalkanols

Formal Total Synthesis of (−)-Taxol

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