Synthesis of aristotelia-type alkaloids. Part X. Biomimetic transformation of synthetic (+)-aristoteline into (−)-alloaristoteline.

Güller, Rolf; Borschberg, Hans‐Jürg

doi:10.1016/s0957-4166(00)82105-9

Cited by 29 publications

(25 citation statements)

References 17 publications

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“…therein. furnished the 2-oxindole derivative (+)-3-epitasmanine ((+)-12) in 85 YO yield. This result remarkably contrasts the previous observation that (-)-6 furnishes almost exclusively the pseudoindoxyl (+)-aristotelone ((+)-2) under the same conditions [9] (see Scheme 2). It seems that the electron-donating properties of the 0-benzoyl group of (-)-15 are insufficient to induce a direct 1,2-rearrangement to (+)-2 (Pathway A ) and that the starting material, therefore, prefers Pathway B oia 16 and the corresponding boat conformer 1 6 to give (+)-3-epitasmanine ((+)-12).…”

Section: )contrasting

confidence: 99%

“…Under more drastic conditions, such as heating for 30 min at 200", (-)-6 rearranged to (+)-aristotelone ((+)-2) in quantitative yield. Under acidic conditions, up to 15 % of (+)-3-epitasmanine ((+)-12) were formed besides (+)-2 [9]. When (-)-6 was treated with NaOEt in EtOH at 25O, it was transformed very slowly into (+)-2 (16% yield after 13 days, 35% after 45 days).…”

Section: Fig Andmentioning

confidence: 99%

“…Consequently, the reaction was repeated at -40°, and under these conditions, (+)-aristoteline ((+)-5) could be oxidized in very high yield and with virtually complete diastereoselectivity to (-)-serratoline ((-)-6) [9]. Yo 32 % (-)-11 a ) 1.…”

mentioning

confidence: 99%

“…e ) 3-C1C6H,C03H, CF3COOH, CH,C12, 1 h, -40O.n 3-C1C6H4C03H, CH,CI2, 10 min reflux. g ) See [9]. h ) 3-C1C6H,C03H, CF3COOH, THF, 100 h, 2 5 O . i) NaOEt, EtOH, 22 h, 25".…”

unclassified

“…This compound was obtained in a one-pot procedure from synthetic (+)-2 (reduction with NaBH,, followed by acid treatment of the resulting 1 : 2 mixture (-)-2O/(-)-2l)I4) [9]). In a different experiment, this mixture was separated by chromatography and the relative configuration of the two epimers determined unambiguously by means of NOE difference experiments (see Scheme 6 and Exper.…”

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confidence: 99%

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Synthesis of Aristotelia‐Type Alkaloids. Part XII. Total synthesis of (−)‐tasmanine. Stereoelectronic factors that control the rearrangement of 3H‐indol‐3‐ol derivatives to oxindoles ( = 1,3‐dihydro‐2H‐indol‐2‐ones) or to pseudoindoxyls ( =1,2‐dihydro‐3H‐indol‐3‐ones)

Güller¹,

Borschberg²

1993

Helvetica Chimica Acta

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The oxidative transformation of (+)‐aristoteline ((+)‐5) into its metabolites, the recently synthesized indole alkaloids (−)‐serratoline ((−)‐6), (+)‐aristotelone ((+)‐2), and (−)‐alloaristoteline ((−)‐22), was investigated in more detail. It was demonstrated that the diastereoface selectivity of the reaction of (+)‐5 with 3‐chloroperbenzoic acid can be altered by variation of the solvent as well as by addition of CF3COOH. The chemoselectivity of the 1,2‐rearrangement of the intermediate 3H‐indol‐3‐ol derivatives could be controlled as follows: treatment of 3H‐indol‐3‐ols with aqueous polyphosphoric acid led to the pseudoindoxyl ( = 1,2‐dihydro‐3H‐indol‐3‐one) derivatives, whereas an analogous treatment of the corresponding O‐benzoates furnished exclusively the corresponding, constitutionally isomeric 2‐oxindole ( = 1,3‐dihydro‐2H‐indol‐2‐one) products. Exploitation of these and related findings led to efficient total syntheses of the Aristotelia alkaloid (−)‐tasmanine ((−)‐1) and of the corresponding unnatural epimer (+)‐12, as well as of the two pseudoindoxyls (+)‐aristotelone ((+)‐2) and (−)‐2‐epiaristotelone ((−)‐11). All these transformations were carried out with synthetic (+)‐aristoteline ((+)‐5) as the single indole alkaloid precursor.

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Section: )contrasting

confidence: 99%

Section: Fig Andmentioning

confidence: 99%

mentioning

confidence: 99%

“…e ) 3-C1C6H,C03H, CF3COOH, CH,C12, 1 h, -40O.n 3-C1C6H4C03H, CH,CI2, 10 min reflux. g ) See [9]. h ) 3-C1C6H,C03H, CF3COOH, THF, 100 h, 2 5 O . i) NaOEt, EtOH, 22 h, 25".…”

unclassified

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confidence: 99%

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Synthesis of Aristotelia‐Type Alkaloids. Part XII. Total synthesis of (−)‐tasmanine. Stereoelectronic factors that control the rearrangement of 3H‐indol‐3‐ol derivatives to oxindoles ( = 1,3‐dihydro‐2H‐indol‐2‐ones) or to pseudoindoxyls ( =1,2‐dihydro‐3H‐indol‐3‐ones)

Güller¹,

Borschberg²

1993

Helvetica Chimica Acta

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The α‐Hydroxy Ketone (α‐Ketol) and Related Rearrangements†

Hofferberth

Paquette

2003

Organic Reactions

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Treatment of suitable alpha‐hydroxy aldehydes and ketones with a base, a Bronsted or Lewis acid, or simply with heat has long been know to induce the 1,2‐shift of an alkyl or aryl substituent to form an isomeric product. The synthetic utility of the process was considerably expanded when applied to steroidal D‐ring homoannulations, and has more recently encompassed novel ring expansion to numerous complex target ring systems. The classical alpha‐ketol rearrangement shares, in common with other base‐promoted ketogenic isomerizations, the property of advancing from an alkoxide to a carbonyl group as the migrating center relocates its bonding electrons to the adjacent trigonal center. A distinctive feature of the title reaction, however, is its reversibility, such that the more stable alpha‐hydroxy carbonyl isomer is favored. The process has sometimes been termed the acyloin rearrangement. This chapter focuses on the isomerization of alpha‐hydroxy ketones, aldehydes, and imines under various reaction conditions exclusive of photochemical activation. The literature coverage extends to 2000. Since many of the steroidal transformations were carried out in early days when products were not always adequately characterized; errors in structural assignment were occasionally made. Experimental detail was sometimes lacking. To alleviate this problem, we have included only experiments that lead to reasonably pure products of established structure.

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InCl₃‐Mediated Addition of Indole to Isatogens: An Expeditious Synthesis of 13‐deoxy‐Isatisine A

Kumar

Puranik

Ramana

2012

Chemistry A European J

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A strategy directed towards the total synthesis of isatisine A that involves several late-stage metal-catalyzed transformations that address the key carbon-carbon and carbon-heteroatom bond formations has been developed. As a part of this strategy, methods for the addition of indoles to isatogens that lead selectively to either 2,2-disubstituted N-hydroxyindolin-3-one or 2,2-disubstituted indolin-3-one compounds have been developed by employing InCl(3) as a catalyst or as the reagent. The present methods provide the first examples of the additions of indoles to the isatogen nucleus. To demonstrate its viability, the synthesis of 13-deoxy-isatisine A has been completed in ten steps from a known and easily available lactone.

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Synthesis of aristotelia-type alkaloids. Part X. Biomimetic transformation of synthetic (+)-aristoteline into (−)-alloaristoteline.

Cited by 29 publications

References 17 publications

Synthesis of Aristotelia‐Type Alkaloids. Part XII. Total synthesis of (−)‐tasmanine. Stereoelectronic factors that control the rearrangement of 3H‐indol‐3‐ol derivatives to oxindoles ( = 1,3‐dihydro‐2H‐indol‐2‐ones) or to pseudoindoxyls ( =1,2‐dihydro‐3H‐indol‐3‐ones)

Synthesis of Aristotelia‐Type Alkaloids. Part XII. Total synthesis of (−)‐tasmanine. Stereoelectronic factors that control the rearrangement of 3H‐indol‐3‐ol derivatives to oxindoles ( = 1,3‐dihydro‐2H‐indol‐2‐ones) or to pseudoindoxyls ( =1,2‐dihydro‐3H‐indol‐3‐ones)

The α‐Hydroxy Ketone (α‐Ketol) and Related Rearrangements†

InCl₃‐Mediated Addition of Indole to Isatogens: An Expeditious Synthesis of 13‐deoxy‐Isatisine A

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Synthesis of aristotelia-type alkaloids. Part X. Biomimetic transformation of synthetic (+)-aristoteline into (−)-alloaristoteline.

Cited by 29 publications

References 17 publications

The α‐Hydroxy Ketone (α‐Ketol) and Related Rearrangements†

InCl3‐Mediated Addition of Indole to Isatogens: An Expeditious Synthesis of 13‐deoxy‐Isatisine A

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InCl₃‐Mediated Addition of Indole to Isatogens: An Expeditious Synthesis of 13‐deoxy‐Isatisine A