Iridium-catalyzed hydroboration of alkenes with pinacolborane

Yamamoto, Yasunori; Fujikawa, Rhyou; Umemoto, Tomokazu; Miyaura, Norio

doi:10.1016/j.tet.2004.09.014

Cited by 167 publications

(128 citation statements)

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“…3 Following on from these early publications, several other methods have been reported for the boryl substitution of alkyl halides using a variety of different transition metal catalysts (e.g., Ni, Pd, Zn and Fe) (Scheme 1a). [4][5][6][7][8] Alkyl halides bearing a terminal alkene moieties can be converted to a variety of borylation products through three different reaction pathways, including the hydroboration of the terminal C=C double bond, 9 borylative cyclization 10 and boryl substitution of the C-X bond (Scheme 1b). Conventional hydroboration reactions allow for the selective reaction of an organoborane compound with a C=C double bond to give the corresponding alkylboron compounds containing a carbon-halogen bond.…”

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confidence: 99%

Copper(i)-catalyzed carbon–halogen bond-selective boryl substitution of alkyl halides bearing terminal alkene moieties

et al. 2015

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COMMUNICATIONThis journal is © The Royal Society of Chemistry 2012 J. Name., 2012, 00, 1-3 | 1 Alkylboronate esters are recognized as useful intermediates in organic synthesis because of their versatility and synthetic utility. 1 Significant research efforts have been devoted to the development of the efficient methods for the synthesis of alkylboron compounds. In this context, the transition metal-catalyzed boryl substitution reactions of alkyl halides have emerged as facile and efficient procedures for the preparation of alkylboronate compounds. Furthermore, these reactions generally exhibit high functional group compatibility compared with conventional organolithium/boron electrophile reactions. Marder et al. were the first group to report the use of a CuCl/PPh 3 /base catalyst system for the boryl substitution of alkyl halides. 2 Almost immediately after this publication, our own group reported the development of a CuCl/Xantphos/base catalyst system that showed similar high levels of activity towards the boryl substitution reactions of alkyl halides. 3 Following on from these early publications, several other methods have been reported for the boryl substitution of alkyl halides using a variety of different transition metal catalysts (e.g., Ni, Pd, Zn and Fe) (Scheme 1a). [4][5][6][7][8] Alkyl halides bearing a terminal alkene moieties can be converted to a variety of borylation products through three different reaction pathways, including the hydroboration of the terminal C=C double bond, 9 borylative cyclization 10 and boryl substitution of the C-X bond (Scheme 1b). Conventional hydroboration reactions allow for the selective reaction of an organoborane compound with a C=C double bond to give the corresponding alkylboron compounds containing a carbon-halogen bond. 9 We recently reported successive papers describing the exo-borylative cyclization reaction of alkyl halides bearing terminal alkene moieties using a CuCl/Xantphos/base catalyst system. 10,11 Despite the success of these researches, the development of a complementally copper-or transition metal-catalyzed reaction for the selective boryl substitution of alkyl halides bearing terminal alkene moieties has been limited. 10,12 In this paper, we have developed a new method for the carbon-halogen bond-selective boryl substitution of alkyl bromides bearing terminal alkene moieties by successful switching the product selectivity through the careful tuning of the catalyst and the ligand. Experimental mechanistic study has also been conducted to develop a thorough understanding of this novel transformation. The reaction of alkyl bromide bearing terminal alkene moieties 1a with bis(pinacolato)diboron (2) was selected as a model reaction to optimize the conditions for the selective copper(I)-catalyzed boryl substitution of alkyl halides bearing terminal alkene moieties, and we began by screening a series of different ligands (Table 1). The initial optimization reactions were performed in the presence of CuCl and a series of different ligands (5 mol %) with 1....

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Copper(i)-catalyzed carbon–halogen bond-selective boryl substitution of alkyl halides bearing terminal alkene moieties

et al. 2015

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“…A similar mechanism has been proposed for reactions of HBcat using early metal and lanthanide catalysts (47). The iridiumcatalysed hydroboration of alkenes using pinacolborane is also known to give the corresponding primary boronate ester products (48,49).…”

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confidence: 58%

Synthesis and catalysed hydroboration of styryl sulfonamides

Wynberg¹,

Leger²,

Conrad³

et al. 2005

Can. J. Chem.

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We have prepared the aryl sulfonamides 4,4′ -R-C 6 H 4 SO 2 NHC 6 H 4 CH=CH 2 (R = CH 3 , 1a; NO 2 , 1b) by addition of 2 equiv. of 4-vinylaniline to the corresponding sulfonyl chlorides. The disulfonamides 4,4,4′ -(R-C 6 H 4 SO 2 ) 2 -NC 6 H 4 CH=CH 2 (R = CH 3 , 2a; NO 2 , 2b) were also prepared using 4-vinylaniline and 2 equiv. of the sulfonyl chlorides in the presence of DMAP. Although hydroborations of sulfanilamide derivatives 1 suffered from competing hydrogenation reactions, judicious choice of the transition metal catalyst gave selective formation of either the primary or secondary boronate esters in hydroborations of 2a.Résumé : On a préparé les aryl sulfonamides, 4,4′ -R-C 6 H 4 SO 2 NHC 6 H 4 CH=CH 2 (R = CH 3 , 1a; NO 2 , 1b) par l'addition de deux équivalents de 4-vinylaniline aux chlorures de sulfonyle correspondants. On a aussi préparé les disulfonamides 4,4,4′ -(R-C 6 H 4 SO 2 ) 2 NC 6 H 4 CH=CH 2 (R = CH 3 , 2a; NO 2 , 2b) à partir de la 4-vinylaniline et de deux équivalents de chlorures de sulfonyle, en présence de DMAP. Quoique les réactions d'hydroboration des dérivés sulfanilamides 1 soient en compétition avec les réactions d'hydrogénation, un choix judicieux d'un catalyseur à base d'un métal de transition permet d'obtenir la formation sélective des boronates soit primaires ou secondaires lors des hydroborations du composé 2a.Mots clés : esters de l'acide boronique, hydroborations catalysées, sulfanilamides, vinylaniline.[Traduit par la Rédaction] Wynberg et al.

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“…Des Weiteren erhält man dadurch die Mçglichkeit der Reaktionskontrolle durch einen Katalysator, um auf diese Weise regioisomere Alkylborane aus gewçhnlichen Edukten zu erhalten. Zum Beispiel entdeckten Crudden et al [74] und Miyaura et al [75] [76] Auf der Basis von NMR-Untersuchungen der mçglichen katalytischen Intermediate konnte postuliert werden, dass die Lewis-Säure die oxidative Addition des Rh I -Katalysators in die H-B-Bindung katalysiert. Eine weitere, vor allem für die industrielle Anwendung wichtige Hydrometallierungsreaktion ist die Hydrosilylierung von Alkenen.…”

Section: Regioselektive Funktionalisierung Von Alkenenunclassified

Katalytische selektive Synthese

2012

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Der Verlauf und das Produkt einer Reaktion lassen sich gezielt über die Katalysatorstruktur steuern, selbst bei nahezu identischen Reaktionsbedingungen. Katalysatorkontrollierte Selektivität ist in der enantioselektiven Synthese gut etabliert, in katalytischen regio‐, chemo‐ und produktselektiven Reaktionen aber wenig verbreitet. Dieser Aufsatz beschreibt, wie eine Ausgangsverbindung lediglich durch die Auswahl des Katalysators selektiv in zwei oder mehr unterschiedliche Produkte umgewandelt werden kann. Wir stellen Beispiele selektiver Katalysen vor und hoffen, dass die bisher erzielten Fortschritte ermutigend für das Gebiet sind. Zugleich wollen auch die noch offenen Fragen beim Entwurf und dem mechanistischen Verständnis selektiver Katalysatoren thematisieren.

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Iridium-catalyzed hydroboration of alkenes with pinacolborane

Cited by 167 publications

References 41 publications

Copper(i)-catalyzed carbon–halogen bond-selective boryl substitution of alkyl halides bearing terminal alkene moieties

Copper(i)-catalyzed carbon–halogen bond-selective boryl substitution of alkyl halides bearing terminal alkene moieties

Synthesis and catalysed hydroboration of styryl sulfonamides

Katalytische selektive Synthese

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