Notes - Compounds Related to Podophyllotoxin. IX. 3,4-Methylenedioxyphenylithium

Gensler, Walter J.; Stouffer, John E.

doi:10.1021/jo01100a609

Cited by 25 publications

(14 citation statements)

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“…This successful approach [8,10] has now been extended to the 3',4'-methylenedioxy example 50 which has the correct aromatic substitution pattern (Scheme 6) for the alkaloid crinine. [34] The required cyclohexadienyliron complex 50 was prepared by generation of the aryllithium reagent [36] from 3,4-methylenedioxybromobenzene, addition to the 1,4-dimethoxy salt 51 (59 %), and reaction with hexafluorophosphoric acid (89 %).…”

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confidence: 99%

“…By recycling in this fashion additional portions of the crude diene complex (31 g and 10 g) were obtained. The combined crude products were purified by chromatography on silica eluting first with light petroleum and then with 10 % Et 2 O in light petroleum to give (in order of elution), tricarbonyl[(1,2,3,4-h)-1-methoxycyclohexa-1,3-diene]iron(0) [21] and tricarbonyl[(1,2,3,4-h)-1,2-dimethoxycyclohexa-1,3-diene]iron(0) (61) (61.2 g, 46 %) [38] [55] (0.804 g, 4 mmol) was dissolved in dry Et 2 O (5 mL) and cooled to À20 8C under nitrogen and n-butyllithium (l.6 m in hexanes) (4 mmol, 2.5 mL) was added to form 1-lithio-3,4-methylenedioxybenzene [36] as a white suspension by stirring for 2 h at À20 8C. Following a modification of the general method E, tricarbonyl[(1,2,3,4,5-h)-1,4-dimethoxycyclohexadienyl]iron(1+) hexafluorophosphate(1À) (51) [8] (1.098 g, 2.59 mmol) was dissolved in dry dichloromethane (10 mL) and cooled to À100 8C.…”

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Selective Synthesis and Reactivity of η⁵‐Arylcyclohexadienyliron Complexes

Owen¹,

Malkov²,

Palotai³

et al. 2007

Chemistry A European J

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A series of aryl-substituted cyclohexadienyliron complexes have been prepared by a general procedure that determines regioselectivity by correctly positioning leaving groups in the precursor complexes. The aryl groups at 1-C or 2-C have been shown to be omega directing by the study of reactions with a representative range of nucleophiles, and these regioselectivity properties have been related to the spectroscopic properties of the cationic cyclohexadienyliron complexes. A high level of electron-donating substituents on the arene, or switching between the [Fe(CO)3] and [Fe(CO)2PPh3] series, reduces the minor ipso pathway, improving regiocontrol. Placing opposed directing groups in the arylcyclohexadienyliron complexes reverts reactivity to the ipso pathway with stabilised enolate nucleophiles, and when the additional directing group reinforces the effect of the aryl group, the ipso pathway is stopped.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Selective Synthesis and Reactivity of η⁵‐Arylcyclohexadienyliron Complexes

Owen¹,

Malkov²,

Palotai³

et al. 2007

Chemistry A European J

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“…Upon double bond equilibration via treatment with iodine, 123 (E)-congured eupomatenoid-15 was obtained 50a in 46% overall yield. In a similar manner, eupomatenoids-3 50b and -4 50c were synthesized from the respective aryl bromides 47b 124 and 47c. In this way a concise and effective synthesis of 2,3,5-trisubstituted benzofurans via three successive cross-coupling reactions were accomplished.…”

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Total synthesis of natural products containing benzofuran rings

et al. 2017

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Research on natural products containing benzofuran has remarkably increased during the past few decades.Newly isolated natural products with complex structures are being studied, characterized and screened for possible biological activities. Several of such compounds have exhibited various biological activities, thus their total syntheses have attracted much attention from synthetic organic chemists. In this review, we aim to highlight the origins, structures, biological potencies, and synthetic approaches of those natural products bearing at least one benzofuran in their complex structures. Furthermore, we especially focus on the step in which this key heterocycle is installed during the total synthesis of a natural product as the desired target.

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“…Compound 10 was then converted to the bromide 11 with N ‐bromosuccinimide and taken further to the key intermediate 12 by a Stille‐type coupling. This reaction where the tributyltin enolate is generated in situ gave the ketone 12 in one step in over 90% yield.…”

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confidence: 99%

Synthesis of [¹³C₆]‐labelled phenethylamine derivatives for drug quantification in biological samples

Karlsen

Liu

Berg

et al. 2014

Labelled Comp Radiopharmac

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The availability of high-quality (13)C-labelled internal standards will improve accurate quantification of narcotics and drugs in biological samples. Thus, the synthesis of 10 [(13)C6]-labelled phenethylamine derivatives, namely amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxy-N-ethylamphetamine, 4-methoxyamphetamine, 4-methoxymethamphetamine, 3,5-dimethoxyphenethylamine 4-bromo-2,5-dimethoxyphenethylamine and 2,5-dimethoxy-4-iodophenethylamine, have been undertaken. [(13)C6]-Phenol proved to be an excellent starting material for making (13)C-labelled narcotic substances in the phenethylamine class, and a developed Stille-type coupling enabled an efficient synthesis of the 3,4-methylenedioxy and 4-methoxy derivatives. The pros and cons of alternative routes and transformations are also discussed. The [(13)C6]-labelled compounds are intended for use as internal standards in forensic analysis, health sciences and metabolomics studies by gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry.

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Notes - Compounds Related to Podophyllotoxin. IX. 3,4-Methylenedioxyphenylithium

Cited by 25 publications

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Selective Synthesis and Reactivity of η⁵‐Arylcyclohexadienyliron Complexes

Selective Synthesis and Reactivity of η⁵‐Arylcyclohexadienyliron Complexes

Total synthesis of natural products containing benzofuran rings

Synthesis of [¹³C₆]‐labelled phenethylamine derivatives for drug quantification in biological samples

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Notes - Compounds Related to Podophyllotoxin. IX. 3,4-Methylenedioxyphenylithium

Cited by 25 publications

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Selective Synthesis and Reactivity of η5‐Arylcyclohexadienyliron Complexes

Selective Synthesis and Reactivity of η5‐Arylcyclohexadienyliron Complexes

Total synthesis of natural products containing benzofuran rings

Synthesis of [13C6]‐labelled phenethylamine derivatives for drug quantification in biological samples

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Product

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Selective Synthesis and Reactivity of η⁵‐Arylcyclohexadienyliron Complexes

Selective Synthesis and Reactivity of η⁵‐Arylcyclohexadienyliron Complexes

Synthesis of [¹³C₆]‐labelled phenethylamine derivatives for drug quantification in biological samples