Palladium‐Catalyzed 2‐Pyridylmethyl Transfer from 2‐(2‐Pyridyl)ethanol Derivatives to Organic Halides by Chelation‐Assisted Cleavage of Unstrained CC Bonds

Niwa, Takashi; Yorimitsu, Hideki; Oshima, Koichiro

doi:10.1002/anie.200604472

Cited by 111 publications

(59 citation statements)

References 30 publications

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“…So können N-Heterocyclen mit elektronenziehenden Gruppen bei 100 8C mit einem Pd-Katalysator aryliert werden. [3] Verschiedene alternative Vorgehensweisen, die die Fragmentierung von 2-(2-Pyridyl)ethanol, [4] die Arylierung von N-Oxiden [5] oder N-Iminopyridiniumyliden [6] umfassen, wurden beschrieben. Diese Methoden sind nun generell, gehen jedoch von modifizierten N-heterocyclischen Ausgangsverbindungen aus.…”

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“…Diese Methoden sind nun generell, gehen jedoch von modifizierten N-heterocyclischen Ausgangsverbindungen aus. [4][5][6] Darüber hinaus kann zwar 2-Picolin (1 a) funktionalisiert werden, wohingegen für 4-Picolin (2 a) keine Arylierung bekannt ist. Die Schwierigkeit, eine neue Kohlenstoff-Kohlenstoff-Bindung mit metalliertem 2-Picolin (3) (oder 4-Picolin) zu knüpfen, kann in der Natur des Palladiumkomplexes [7] (4 a-c) liegen, welcher aus der Reaktion mit ArPdX hervorgeht (Schema 1).…”

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“…[25] Dennoch findet nach Zusatz von 10 Mol-% Sc(OTf) 3 eine effektive Pd-katalysierte Kreuzkupplung statt, die das Produkt 6 g in 87 % Ausbeute liefert (Schema 3). In derselben Weise ergibt 4-Picolin (2 a) das Kreuzkupplungsprodukt 10 j in nur 41 % Ausbeute ohne Sc(OTf) 3 , wohingegen der Zusatz von 10 Mol-% Sc(OTf) 3 Bei Negishi-Kreuzkupplungen mit Arylbromiden, die azide Protonen enthalten, erwies sich die Verwendung von Pd(OCOCF 3 ) 2 , eingeführt von Oshima und Yorimitsu, [4] als vorteilhaft für schnelle Umsetzungen und hohe Ausbeuten (Nr. 4 und 5).…”

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Lewis‐Säure‐vermittelte benzylische Kreuzkupplungen von Pyridinen mit Arylbromiden

Duez¹,

Steib²,

Manolikakes³

et al. 2011

Angewandte Chemie

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ZnCl2, Sc(OTf)3 oder BF3⋅OEt2 vermitteln die Pd‐katalysierte Arylierung von Methylpyridinen und ähnlichen Heterocyclen (siehe Beispiel). Die Komplexierung des Stickstoffatoms im Heterocyclus durch die Lewis‐Säure erleichtert die reduktive Eliminierung, was in hohen Ausbeuten zu zahlreichen arylierten Produkten führt. Mit BF3⋅OEt2 gelingt darüber hinaus im Fall des 2,4‐Lutidins eine hoch regioselektive Metallierung.

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Lewis‐Säure‐vermittelte benzylische Kreuzkupplungen von Pyridinen mit Arylbromiden

Duez¹,

Steib²,

Manolikakes³

et al. 2011

Angewandte Chemie

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“…27 Pyrazinyl alcohol 44 also underwent a similar reaction (eq 1). However, a 4-pyridylmethyl group as well as a benzyl group was not transferred from the corresponding alcohols under conditions we extensively tested.…”

Section: Palladium-catalyzed 2-pyridylmethyl Transfermentioning

confidence: 91%

Metal-Mediated Retro-Allylation of Homoallyl Alcohols for Highly Selective Organic Synthesis

Yorimitsu

Oshima

2009

Bulletin of the Chemical Society of Japan

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Metal-mediated or -catalyzed retro-allylation of homoallyl alcohol that proceeds via a six-membered transition state has appeared as a new useful method to prepare allylmetals. A crotylzirconium reagent undergoes stereoselective allylation of aromatic aldehyde at ¹78 and 25°C to provide threo-and erythro-homoallyl alcohols, respectively. Although the threo isomer is formed as usual via a six-membered chair transition state under kinetic control, the erythro selectivity is rationalized by considering isomerization of the threo adduct through a retro-allylation process. The retroallylation of a bulky gallium homoallyloxide occurs to generate (Z)-and (E)-crotylgallium reagents stereospecifically, starting from erythro-and threo-homoallyl alcohols, respectively. The (Z)-and (E)-crotylgallium reagents react with aromatic aldehydes in situ to afford the corresponding erythro-and threo-homoallyl alcohols, respectively. Treatment of rationally designed tertiary homoallyl alcohols with aryl halides under palladium catalysis yielded the corresponding allylarenes stereo-and regioselectively, by replacing the conventional transmetalation step in the cross-coupling reaction with alkoxidehalide exchange followed by a retro-allylation reaction. The retro-allylation reaction is also applicable to nickel and rhodium at this stage, and may to any other metals in principle. Reversible additions of pentamethylcyclopentadienyl anion to carbonyl compounds are also described.

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“…The reaction of 2-(pyridylmethyl) toluene (1b) 35,36) under the optimal conditions gave benzocyclobutene 3ba in 81% yield. The 2-pyrimidylmethyl and pyridyl-2-oxy bearing substrates 1c and d also performed well in this transformation, affording the corresponding cyclobutene products 3ca and da in lower yields.…”

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confidence: 99%

Palladium-Catalyzed Double C–H Functionalization of Arenes at the Positions <i>ortho</i> and <i>meta</i> to Their Directing Group: Concise Synthesis of Benzocyclobutenes

Nanjo

Tsukano

Takemoto

2016

CHEMICAL & PHARMACEUTICAL BULLETIN

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The synthesis of benzocyclobutenes from simple arenes bearing a directing group was investigated via the palladium-catalyzed cyclization of norbornene derivatives. This approach allowed for the facile construction of benzocyclobutenes along with the double functionalization of the C-H bonds at the positions ortho and meta to the directing group. This result shows that the key palladacyclopentene intermediate in the Catellani reaction can be prepared by the directed double ortho C-H activation of the substrate. The results of this study also revealed that the combination of an N-protected amino acid with benzoquinone (BQ) was effective for this transformation.

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Palladium‐Catalyzed 2‐Pyridylmethyl Transfer from 2‐(2‐Pyridyl)ethanol Derivatives to Organic Halides by Chelation‐Assisted Cleavage of Unstrained CC Bonds

Cited by 111 publications

References 30 publications

Lewis‐Säure‐vermittelte benzylische Kreuzkupplungen von Pyridinen mit Arylbromiden

Lewis‐Säure‐vermittelte benzylische Kreuzkupplungen von Pyridinen mit Arylbromiden

Metal-Mediated Retro-Allylation of Homoallyl Alcohols for Highly Selective Organic Synthesis

Palladium-Catalyzed Double C–H Functionalization of Arenes at the Positions <i>ortho</i> and <i>meta</i> to Their Directing Group: Concise Synthesis of Benzocyclobutenes

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