Influences on the Relative Rates for C−N Bond-Forming Reductive Elimination and β-Hydrogen Elimination of Amides. A Case Study on the Origins of Competing Reduction in the Palladium-Catalyzed Amination of Aryl Halides

1996 ◽  
Vol 118 (15) ◽  
pp. 3626-3633 ◽  
Author(s):  
John F. Hartwig ◽  
Steven Richards ◽  
David Barañano ◽  
Frédéric Paul
Keyword(s):  
Reductive Elimination ◽  
Aryl Halides ◽  
Bond Forming ◽  
Hydrogen Elimination ◽  
Palladium Catalyzed

Selective organometallic syntheses from molecular pools

2002 ◽  
Vol 74 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Marta Catellani
Keyword(s):  
High Selectivity ◽  
Oxidative Addition ◽  
Reductive Elimination ◽  
Selective Synthesis ◽  
Aryl Iodide ◽  
Bond Forming ◽  
Mild Conditions ◽  
Palladium Catalyzed ◽  
Selective Alkylation ◽  
Sequential Processes

A new methodology is described, consisting of the use of molecular pools in palladium-catalyzed sequential processes occurring under mild conditions with high selectivity. These reactions involve palladacycle formation from aryl iodide, palladium, and norbornene, the latter behaving as a second catalyst that is first incorporated into the metallacycle and expelled at the end of the process. Selective alkylation or arylation of the arene nucleus occurring by oxidative addition/reductive elimination of palladacycles are coupled, after norbornene expulsion, with C­H or C­C bond-forming reactions such as hydrogenolysis, olefin insertion, arylboronic coupling, etc. The variety of possible combinations offers a powerful tool for the selective synthesis of unusual and not readily accessible aromatics.

scholarly journals Focusing on the Catalysts of the Pd- and Ni-Catalyzed Hirao Reactions

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3897
Author(s):  
György Keglevich ◽  
Réka Henyecz ◽  
Zoltán Mucsi
Keyword(s):  
Experimental Data ◽  
Transition Metal ◽  
Ligand Exchange ◽  
Theoretical Calculations ◽  
Reductive Elimination ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Aryl Halides ◽  
Feature Article ◽  
Bond Forming

The Hirao reaction involving the phosphinoylation or phosphonation of aryl halides by >P(O)H reagents is a P–C bond forming transformation belonging to the recently very hot topic of cross-couplings. The Pd- or Ni-catalyzed variations take place via the usual cycle including oxidative addition, ligand exchange, and reductive elimination. However, according to the literature, the nature of the transition metal catalysts is not unambiguous. In this feature article, the catalysts described for the Pd(OAc)2-promoted cases are summarized, and it is concluded that the “(HOY2P)2Pd(0)” species (Y = aryl, alkoxy) is the real catalyst. In our model, the excess of the >P(O)H reagent served as the P-ligand. During the less studied Ni(II)-catalyzed instances the “(HOY2P)(−OY2P)Ni(II)Cl−” form was found to enter the catalytic cycle. The newest conclusions involving the exact structure of the catalysts, and the mechanism for their formation explored by us were supported by our earlier experimental data and theoretical calculations.

Carbon-Heteroatom Cross-Coupling via an Electronically Excited Nickel (II) Complex

2019 ◽  
Author(s):  
Randolph Escobar ◽  
Jeffrey Johannes
Keyword(s):  
Energy Transfer ◽  
Functional Groups ◽  
Cross Coupling ◽  
Reductive Elimination ◽  
Aryl Halides ◽  
Coupling Reactions ◽  
General Methodology ◽  
Cross Coupling Reactions ◽  
Electronically Excited ◽  
Energy Transfer Pathway

<div>While carbon-heteroatom cross coupling reactions have been extensively studied, many methods are specific and</div><div>limited to a set of substrates or functional groups. Reported here is a method that allows for C-O, C-N and C-S cross coupling reactions under one general methodology. We propose that an energy transfer pathway, in which an iridium photosensitizer produces an excited nickel (II) complex, is responsible for the key reductive elimination step that couples aryl halides to 1° and 2° alcohols, anilines, thiophenols, carbamates and sulfonamides.</div>

Palladium Catalyzed Cascade Azidation/Carbonylation of Aryl Halides with Sodium Azide for the Synthesis of Amides

2021 ◽  
Author(s):  
Zhuang Qi ◽  
Shan‐Shan Li ◽  
Lin Li ◽  
Qi Qin ◽  
Li‐Miao Yang ◽  
...  
Keyword(s):  
Sodium Azide ◽  
Aryl Halides ◽  
Palladium Catalyzed
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