Short synthesis of the C<sub>16</sub>–C<sub>28</sub>polyketide fragment of apoptolidin A aglycone

Craita, Cotinica; Didier, Charles; Vogel, Pierre

doi:10.1039/b701293d

Cited by 16 publications

(10 citation statements)

References 48 publications

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“…Applying our reaction cascade to diene 55 and enoxysilane 56, we have realized a rapid access (9 steps) to Koert's C 16 -C 28 polyketide fragment 64 (Scheme 8) of apoptolidinones A and D [156]. This fragment is adequately protected for the glycosidation steps necessary in the construction of 51.…”

Section: Methodsmentioning

confidence: 99%

Use of sultines in the asymmetric synthesis of polypropionate antibiotics

Vogel

Turks

Bouchez

et al. 2008

Pure and Applied Chemistry

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At low temperature and in the presence of an acid catalyst, SO 2 adds to 1,3-dienes equilibrating with the corresponding 3,6-dihydro-1,2-oxathiin-2-oxides (sultines). These compounds are unstable above -60°C and equilibrate with the more stable 2,5-dihydrothiophene 1,1-dioxides (sulfolenes). The hetero-Diels-Alder additions of SO 2 are suprafacial and follow the Alder endo rule. The sultines derived from 1-oxy-substituted and 1,3-dioxydisubstituted 1,3-dienes cannot be observed at -100°C but are believed to be formed faster than the corresponding sulfolenes. In the presence of acid catalysts, the 6-oxy-substituted sultines equilibrate with zwitterionic species that react with electron-rich alkenes such as enoxysilanes and allylsilanes, generating β,γ-unsaturated silyl sulfinates that can be desilylated and desulfinylated to generate polypropionate fragments containing up to three contiguous stereogenic centers and an (E)-alkene unit. Alternatively, the silyl sulfinates can be reacted with electrophiles to generate polyfunctional sulfones (one-pot, four-component synthesis of sulfones), or oxidized into sulfonyl chlorides and reacted with amines, then realizing a one-pot, four-component synthesis of polyfunctional sulfonamides. Using enantiomerically enriched dienes such as 1-[(R)-or 1-(S)-phenylethyloxy]-2-methyl-(E,E)-penta-1,3-dien-3-yl isobutyrate, derived from inexpensive (R)-or (S)-1-phenylethanol, enantiomerically enriched stereotriads are obtained in one-pot operations. The latter are ready for further chain elongation. This has permitted the development of expeditious total asymmetric syntheses of important natural products of biological interest such as the baconipyrones, rifamycin S, and apoptolidin A.

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Section: Methodsmentioning

confidence: 99%

Use of sultines in the asymmetric synthesis of polypropionate antibiotics

Vogel

Turks

Bouchez

et al. 2008

Pure and Applied Chemistry

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“…Aldol reactions of ketones of type 7 have permitted expeditious asymmetric syntheses of the C(19)-C (27) stereoheptad of the rifamycins [15] and of Koert's C(16)-C(28) fragment of apoptolidin A. [16] The stereotriads 7, each with an alkenyl ester, in fact each contain two structural motifs for direct two-directional chain elongation through two successive aldol reactions. On one hand, the ketone moiety can be used directly in a first aldol reaction (Scheme 2).…”

Section: Introductionmentioning

confidence: 99%

Efficient Asymmetric Synthesis of Long‐Chain Polyketides Containing up to Ten Contiguous Stereogenic Centres by Double Chain Elongation

et al. 2011

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The 2,3-anti-3,4-syn-stereotriad (1Z,2S,3R,4S)-1-ethylidene-2,4-dimethyl-3-[(1S)-1-phenylethoxy]-5-oxopent-1-yl isobutyrate {(-)-8, obtained in a one-pot operation from the trimethylsilyl (Z)-enol ether derived from pentan-3-one and (1E,3Z)-1[(1S)-phenylethoxy]-2-methylpenta-1,3-dien-3-yl isobutyrate through SO 2 umpolung} contains an ethyl ketone moiety that undergoes diastereoselective cross-aldol reactions with acetaldehyde. After subsequent reductions, various diastereomeric stereohexads (polypropionate fragments containing six contiguous stereogenic centres) in which the

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“…To initiate our synthetic effort, we prepared enol ether 9 using the sequence shown in Scheme . Known vinylogous ester 10 underwent silylation/Rubottom oxidation to give an intermediate α-siloxy ketone . Subsequent ketone reduction and acetylation , provided allylic acetate 11 as a 1:1 diastereomeric mixture in 56% yield over the two steps.…”

Section: Resultsmentioning

confidence: 99%

Total Synthesis of (−)-Strictosidine and Interception of Aryne Natural Product Derivatives “Strictosidyne” and “Strictosamidyne”

et al. 2021

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Monoterpene indole alkaloids are a large class of natural products derived from a single biosynthetic precursor, strictosidine. We describe a synthetic approach to strictosidine that relies on a key facially selective Diels–Alder reaction between a glucosyl-modified alkene and an enal to set the C15–C20–C21 stereotriad. DFT calculations were used to examine the origin of stereoselectivity in this key step, wherein two of 16 possible isomers are predominantly formed. These calculations suggest the presence of a glucosyl unit, also inherent in the strictosidine structure, guides diastereoselectivity, with the reactive conformation of the vinyl glycoside dienophile being controlled by an exo-anomeric effect. (−)-Strictosidine was subsequently accessed using late-stage synthetic manipulations and an enzymatic Pictet–Spengler reaction. Several new natural product analogs were also accessed, including precursors to two unusual aryne natural product derivatives termed “strictosidyne” and “strictosamidyne”. These studies provide a strategy for accessing glycosylic natural products and a new platform to access monoterpene indole alkaloids and their derivatives.

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Short synthesis of the C₁₆–C₂₈polyketide fragment of apoptolidin A aglycone

Abstract: Starting from (E,E)-1-[(1R)-(phenylethyl)oxy]-2-methylpenta-1,3-diene and triethylsilyl enol ether of butanone rapid access to Koert's advanced C10-C28 polyketide fragment of apoptolidin A is now possible.

Cited by 16 publications

References 48 publications

Use of sultines in the asymmetric synthesis of polypropionate antibiotics

Use of sultines in the asymmetric synthesis of polypropionate antibiotics

Efficient Asymmetric Synthesis of Long‐Chain Polyketides Containing up to Ten Contiguous Stereogenic Centres by Double Chain Elongation

Total Synthesis of (−)-Strictosidine and Interception of Aryne Natural Product Derivatives “Strictosidyne” and “Strictosamidyne”

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Short synthesis of the C16–C28polyketide fragment of apoptolidin A aglycone

Abstract: Starting from (E,E)-1-[(1R)-(phenylethyl)oxy]-2-methylpenta-1,3-diene and triethylsilyl enol ether of butanone rapid access to Koert's advanced C10-C28 polyketide fragment of apoptolidin A is now possible.

Cited by 16 publications

References 48 publications

Use of sultines in the asymmetric synthesis of polypropionate antibiotics

Use of sultines in the asymmetric synthesis of polypropionate antibiotics

Efficient Asymmetric Synthesis of Long‐Chain Polyketides Containing up to Ten Contiguous Stereogenic Centres by Double Chain Elongation

Total Synthesis of (−)-Strictosidine and Interception of Aryne Natural Product Derivatives “Strictosidyne” and “Strictosamidyne”

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Short synthesis of the C₁₆–C₂₈polyketide fragment of apoptolidin A aglycone