Synthesis of 4-substituted phenylalanines by cross-coupling reactions: Extension of the methodology to aryl chlorides

Firooznia, Fariborz; Gude, Candido; Chan, Kalok; Satoh, Yoshitaka

doi:10.1016/s0040-4039(98)00749-7

Cited by 66 publications

(16 citation statements)

References 7 publications

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“…Firooznia et al subsequently applied Pd/PCy 3 to Suzuki cross‐couplings of activated aryl chlorides with boronate esters to generate 4‐substituted phenylalanines protected with a tert ‐butoxycarbonyl (Boc) group [Eq. (8)] 45. Unfortunately, attempts to extend this chemistry to the synthesis of enantiopure 4‐aryl‐substituted phenylalanines led to nearly racemic products 46…”

Section: Carbon–carbon Bond‐forming Reactionsmentioning

confidence: 99%

Palladium-Catalyzed Coupling Reactions of Aryl Chlorides

Littke

2002

Angew. Chem. Int. Ed.

2,714

1,214

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Collectively, palladium-catalyzed coupling reactions represent some of the most powerful and versatile tools available to synthetic organic chemists. Their widespread popularity stems in part from the fact that they are generally tolerant to a large number of functional groups, which allows them to be employed in a wide range of applications. However, for many years a major limitation of palladium-catalyzed coupling processes has been the poor reactivity of aryl chlorides, which from the standpoints of cost and availability are more attractive substrates than the corresponding bromides, iodides, and triflates. Traditional palladium/triarylphosphane catalysts are only effective for the coupling of certain activated aryl chlorides (for example, heteroaryl chlorides and substrates that bear electron-withdrawing groups), but not for aryl chlorides in general. Since 1998, major advances have been described by a number of research groups addressing this challenge; catalysts based on bulky, electron-rich phosphanes and carbenes have proved to be particularly mild and versatile. This review summarizes both the seminal early work and the exciting recent developments in the area of palladium-catalyzed couplings of aryl chlorides.

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Section: Carbon–carbon Bond‐forming Reactionsmentioning

confidence: 99%

Palladium-Catalyzed Coupling Reactions of Aryl Chlorides

Littke

2002

Angew. Chem. Int. Ed.

2,714

1,214

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“…Daraufhin setzten Firooznia et al Pd/PCy 3 für Suzuki‐Kreuzkupplungen aktivierter Arylchloride mit Boronsäureestern ein, um Boc‐geschützte 4‐substituierte Phenylalanine herzustellen [Gl. (8)] 45. Leider führten Versuche, diese Chemie auf die Synthese enantiomerenreiner 4‐arylsubstituierter Phenylalanine zu übertragen, zu nahezu racemischen Produkten 46…”

Section: Reaktionen Zur Knüpfung Von Kohlenstoff‐kohlenstoff‐binduunclassified

Palladiumkatalysierte Kupplungen von Arylchloriden

2002

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Palladiumkatalysierte Kupplungen gehören zu den leistungsfähigsten und vielseitigsten Reaktionen, die dem organischen Chemiker für die Synthese zur Verfügung stehen. Ihre große Beliebtheit rührt teilweise daher, dass sie bei den Umsetzungen gewöhnlich viele funktionelle Gruppen tolerieren, was ihre breite Verwendung in vielen Bereichen ermöglicht. Allerdings unterlagen die palladiumkatalysierten Kupplungen jahrelang großen Einschränkungen durch die geringe Reaktivität der Arylchloride; diese Verbindungen sind in Bezug auf Kosten und Verfügbarkeit attraktivere Substrate als die entsprechenden Bromide, Iodide und Triflate. Herkömmliche Palladium/Triarylphosphan‐Katalysatoren setzten nur bestimmte aktivierte Arylchloride um (z. B. Heteroarylchloride und Substrate mit elektronenanziehenden Gruppen), nicht aber Arylchloride generell. Seit 1998 haben mehrere Forschungsgruppen bedeutende Fortschritte hinsichtlich dieser Herausforderung beschrieben; Katalysatoren mit voluminösen, elektronenreichen Phosphanen und Carbenen erwiesen sich als sehr vielseitig und ermöglichen besonders milde Reaktionsbedingungen. Dieser Aufsatz fasst die frühen, wegweisenden Arbeiten und die spannenden neuartigen Entwicklungen auf dem Gebiet der palladiumkatalysierten Kupplungen von Arylchloriden zusammen.

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“…45 Later, catalytic amounts of PdCl 2 (PCy 3 ) 2 , or of the system composed of Pd 2 (dba) 3 and PCy 3 , were used for efficient Suzuki reactions of aryl chlorides with boronate esters. [46][47][48] Moreover, through the use of the catalyst system consisting of 5 mol% PdCl 2 and 10 mol% PCy 3 it was possible to synthesise 5-substituted arylfurfurals from 5-formyl-2-furylboronic acid and aryl bromides or iodides (Scheme 4). 49 The observations made by Shen 45 were confirmed by Monteith,50,51 who, during the development of a manifacturing route to 2-cyano-4¢-methylbiphenyl, found that electron-rich and bulky phosphines such as PCy 3 , P(i-Pr) 3 and P(i-Bu) 3 are very efficient ligands for Suzuki palladium-catalysed reactions involving activated aryl chlorides.…”

Section: Figure 2amentioning

confidence: 99%

Untitled

2004

Synthesis

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This review with 206 references covers the literature published until March 2004 on the development and applications of new efficient catalyst systems for the Suzuki palladium-catalysed cross-coupling reaction of organoboron compounds with organic electrophiles. Where possible, the relative advantages of the new catalyst systems in this synthetically very important carbon-carbon bond forming reaction have been compared.

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Synthesis of 4-substituted phenylalanines by cross-coupling reactions: Extension of the methodology to aryl chlorides

Cited by 66 publications

References 7 publications

Palladium-Catalyzed Coupling Reactions of Aryl Chlorides

Palladium-Catalyzed Coupling Reactions of Aryl Chlorides

Palladiumkatalysierte Kupplungen von Arylchloriden

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