Namen- und Schlagwort-Reaktionen der Organischen Chemie

Laue, Thomas; Plagens, Andreas

doi:10.1007/978-3-322-94726-0

Cited by 5 publications

(4 citation statements)

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“…[23] In principle it is an electrophilic aromatic substitution between a diazonium salt A5 and an electron rich aromatic compound A6 (Scheme 1). [24] Since the reaction mechanism follows the pathway of an electrophilic aromatic substitution reaction, due to electronic reasons and steric hindrance, the substitution mainly occurs in the para position to the activating group and only if the para position is blocked ortho substitution is observed. [24][ 25] Scheme 1 Mechanism of the azo coupling.…”

Section: Azo Coupling Reaction (Electrophilic Aromatic Substitution)mentioning

confidence: 99%

“…[24] Since the reaction mechanism follows the pathway of an electrophilic aromatic substitution reaction, due to electronic reasons and steric hindrance, the substitution mainly occurs in the para position to the activating group and only if the para position is blocked ortho substitution is observed. [24][ 25] Scheme 1 Mechanism of the azo coupling. [24] (A) The formation of the diazonium salt A5.…”

Section: Azo Coupling Reaction (Electrophilic Aromatic Substitution)mentioning

confidence: 99%

“…[191] [192][194] [224] As it was a key reaction in the assembly of all target semicircles 11, 16, 32 and 43, the mechanism including the catalytic cycle is shown in Scheme 24 and will be briefly discussed. [24] [207] The coupling takes place between an organoboronic acid and aryl halides. Recent catalyst and methods developments have broadened the possible applications enormously, so that the scope of the reaction partners is not restricted to aryls, but includes alkyls, alkenyls and alkynyls.…”

Section: Mechanism Of Suzuki Cross Coupling Reactionmentioning

confidence: 99%

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Shape‐Switchable Azo‐Macrocycles

et al. 2009

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The synthesis of four shape‐switchable macrocycles comprising different peripheral substituents is described. The macrocycles 1–4 consist of m‐terphenyl semicircles interlinked by two azo joints. These macrocycles were assembled from nitro‐functionalized m‐terphenyl moieties through reductive dimerization. The semicircles were assembled through Suzuki cross‐coupling reactions. The molecular weights of the macrocycles were determined by vapour pressure osmometry, because mass spectrometry failed in the cases of 2 and 3. The E → Z photoisomerization reactions were analysed by UV/Vis spectroscopy complemented by 1H NMR studies. A very slow thermal back‐reaction indicated considerable stabilization of the Z isomer. The reduced efficiency of the thermal back‐reaction probably arises from the reduced degree of freedom due to the mechanical interlinking of the two azo groups. The photostationary state consisted of all‐Z (85 %) and all‐E isomers (15 %). The E → Z transformation induced by irradiation displayed simple exponential kinetics, which indicates pairwise switching of the two azo groups in a macrocycle, at least on the timescale under investigation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Section: Azo Coupling Reaction (Electrophilic Aromatic Substitution)mentioning

confidence: 99%

Section: Azo Coupling Reaction (Electrophilic Aromatic Substitution)mentioning

confidence: 99%

Section: Mechanism Of Suzuki Cross Coupling Reactionmentioning

confidence: 99%

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Shape‐Switchable Azo‐Macrocycles

et al. 2009

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“…The leaving of an acyl group corresponds in principle to the back reaction of a Friedel–Crafts acylation. 37 The latter is actually considered an irreversible reaction, 45 which makes this mechanism very unusual. Subsequently, a 5- exo -cyclization to the benzylic cation Int 9 takes place, overcoming a barrier of 5.3 kcal/mol.…”

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confidence: 99%

Gold(I)-Catalyzed Dearomatization–Allenene Reaction for the Construction of Polycycles with Excellent Diastereoselectivity

Semleit

Haberhauer

2023

Synthesis

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The synthesis of complex polycycles starting from simple building blocks in just a few reaction steps is usually very challenging. Herein, we present the gold(I)-catalyzed synthesis of various polycycles via dearomatization–allenene reaction of aryl propargyl ethers with different nucleophiles. Depending on the starting material, polycycles can be isolated in yields up to 94% and with an enantiomeric excess of 95%. Quantum chemical calculations show that for all starting materials a Claisen rearrangement to the allenene occurs in the first reaction sequence. The subsequent cyclization and reaction with a nucleophile leads to various polycycles with the formation of up to six new C–C bonds in only one reaction step. All reactions proceed with excellent diastereoselectivity, with a α-quaternary carbonyl carbon present in the products.

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