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 Palladium-catalyzed regio- and stereoselective synthesis of aryl and 3-indolyl-substituted 4-methylene-3,4-dihydroisoquinolin-1(2H)-ones

2020 ◽  
Vol 16 ◽  
pp. 1084-1091 ◽  
Author(s):  
Valeria Nori ◽  
Antonio Arcadi ◽  
Armando Carlone ◽  
Fabio Marinelli ◽  
Marco Chiarini
Keyword(s):  
Stereoselective Synthesis ◽  
Reductive Elimination ◽  
Aryl Iodide ◽  
Arylboronic Acids ◽  
Palladium Catalyzed

Cascade cyclocarbopalladation of the readily available aryl/alkyl-substituted propargylic amides containing an aryl iodide moiety, followed by Suzuki–Miyaura coupling with arylboronic acids, allowed an efficient regio- and stereoselective synthesis of tetrasubstituted 4-methylene-3,4-dihydroisoquinolin-1(2H)-ones. Moreover, cascade cyclocarbopalladation, followed by the reaction with 2-alkynyltrifluoroacetanilides, accomplished a double cyclization to afford challenging 4-methylene-3,4-dihydroisoquinolin-1(2H)-ones bearing a 3-indolyl substituent through aminopalladation/reductive elimination.

Palladium-catalyzed Si–C bond-forming silylation of aryl iodides with hydrosilanes: an enhanced enantioselective synthesis of silicon-stereogenic silanes by desymmetrization

RSC Advances ◽  
2016 ◽  
Vol 6 (71) ◽  
pp. 67113-67117 ◽  
Author(s):  
Li Chen ◽  
Jiang-Bo Huang ◽  
Zheng Xu ◽  
Zhan-Jiang Zheng ◽  
Ke-Fang Yang ◽  
...  
Keyword(s):  
Enantioselective Synthesis ◽  
Carbon Bond ◽  
Bond Forming ◽  
Mild Conditions ◽  
Aryl Iodides ◽  
Silicon Carbon ◽  
Palladium Catalyzed ◽  
Silylation Reaction

An enantioselective Pd-catalyzed silicon–carbon bond-forming silylation reaction of aryl iodides with hydrosilanes for the synthesis of silicon-stereogenic silanes has been developed with good enantioselectivity under mild conditions.

scholarly journals Palladium-Catalyzed Regio- and Stereoselective Synthesis of Aryl and 3-Indolyl Substituted-4-Methylene- isoquinolin-1(2H)-ones.

2020 ◽  
Author(s):  
Valeria Nori ◽  
Antonio Arcadi ◽  
Armando Carlone ◽  
Fabio Marinelli ◽  
Marco Chiarini
Keyword(s):  
Stereoselective Synthesis ◽  
Reductive Elimination ◽  
Aryl Iodide ◽  
Arylboronic Acids ◽  
Palladium Catalyzed

Cascade cyclocarbopalladation of the readily available aryl/alkyl-substituted propargylic amides containing an aryl iodide moiety, followed by Suzuki-Miyaura coupling with arylboronic acids, allowed an efficient regio- and stereoselective synthesis of tetrasubstituted-4-methylene-isoquinolin-1(2H)-ones. Moreover cascade cyclocarbopalladation, followed by reaction with 2- alkynyltrifluoroacetanilides, accomplished a double cyclization, to afford challenging 4-methylene-isoquinolin-1(2H)-ones bearing a 3-indolyl substituent, through aminopalladation/reductive elimination

Palladium-Catalyzed Allylation of Polyfluoroarenes with Allylic Pivalates

Synlett ◽  
2017 ◽  
Vol 29 (02) ◽  
pp. 251-255
Author(s):  
Xinpeng Jiang ◽  
Yong Liu ◽  
Lei Zhang ◽  
Jinkang Chen ◽  
Kang Cheng ◽  
...  
Keyword(s):  
Catalytic System ◽  
Good Yield ◽  
Functional Group ◽  
Palladium Complex ◽  
Oxidative Addition ◽  
Reductive Elimination ◽  
Nucleophilic Attack ◽  
Palladium Catalyzed ◽  
Mechanistic Investigations

An efficient 1,5-cyclooctadiene–PdCl2/dicyclohexyl(2′,4′,6′-triisopropylbiphenyl-2-yl)phosphine (XPhos) catalytic system was developed for C–H allylation of polyfluoroarenes with allylic pivalates. The reactions showed excellent functional-group tolerance, good yields, and high regioselectivities. Mechanistic investigations supported a (π-allyl)palladium complex pathway through a directed oxidative addition of the allylic pivalate to palladium, followed by sequential nucleophilic attack by the polyfluorobenzene and reductive elimination. In a gram-scale reaction, a palladium loading of 0.5 mol% was enough to afford the required product in good yield.

A dual light-driven palladium catalyst: Breaking the barriers in carbonylation reactions

Science ◽  
2020 ◽  
Vol 368 (6488) ◽  
pp. 318-323 ◽  
Author(s):  
Gerardo M. Torres ◽  
Yi Liu ◽  
Bruce A. Arndtsen
Keyword(s):  
Bond Cleavage ◽  
Oxidative Addition ◽  
Reductive Elimination ◽  
Coupling Reactions ◽  
Ambient Conditions ◽  
Inherent Limitation ◽  
Carbonyl Derivatives ◽  
Palladium Catalyzed ◽  
Light Excitation ◽  
Metal Catalyzed

Transition metal–catalyzed coupling reactions have become one of the most important tools in modern synthesis. However, an inherent limitation to these reactions is the need to balance operations, because the factors that favor bond cleavage via oxidative addition ultimately inhibit bond formation via reductive elimination. Here, we describe an alternative strategy that exploits simple visible-light excitation of palladium to drive both oxidative addition and reductive elimination with low barriers. Palladium-catalyzed carbonylations can thereby proceed under ambient conditions, with challenging aryl or alkyl halides and difficult nucleophiles, and generate valuable carbonyl derivatives such as acid chlorides, esters, amides, or ketones in a now-versatile fashion. Mechanistic studies suggest that concurrent excitation of palladium(0) and palladium(II) intermediates is responsible for this activity.

Synthesis of S-aryl thioesters via palladium-catalyzed thiocarbonylation of aryl iodides and aryl sulfonyl hydrazides

2020 ◽  
Vol 7 (19) ◽  
pp. 2938-2943
Author(s):  
Yeojin Kim ◽  
Kwang Ho Song ◽  
Sunwoo Lee
Keyword(s):  
Aryl Iodide ◽  
Aryl Iodides ◽  
Palladium Catalyzed

Aryl sulfonyl hydrazide reacted with aryl iodide in the presence of CO to give the corresponding S-aryl thioesters.

Reversible Oxidative-Addition and Reductive-Elimination of Thiophene from a Titanium Complex and Its Thermally-Induced Hydrodesulfurization Chemistry

2019 ◽  
Author(s):  
Alejandra Gomez-Torres ◽  
J. Rolando Aguilar-Calderón ◽  
Carlos Saucedo ◽  
Aldo Jordan ◽  
Alejandro J. Metta-Magaña ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Ring Opening ◽  
Thiophene Ring ◽  
Oxidative Addition ◽  
Reductive Elimination ◽  
Thermally Induced ◽  
Titanium Complex

<p>The masked Ti(II) synthon (<sup>Ket</sup>guan)(<i>η</i><sup>6</sup>-Im<sup>Dipp</sup>N)Ti (<b>1</b>) oxidatively adds across thiophene to give ring-opened (<sup>Ket</sup>guan)(Im<sup>Dipp</sup>N)Ti[<i>κ</i><sup>2</sup>-<i>S</i>(CH)<sub>3</sub><i>C</i>H] (<b>2</b>). Complex <b>2</b> is photosensitive, and upon exposure to light, reductively eliminates thiophene to regenerate <b>1</b> – a rare example of early-metal mediated oxidative-addition/reductive-elimination chemistry. DFT calculations indicate strong titanium π-backdonation to the thiophene π*-orbitals leads to the observed thiophene ring opening across titanium, while a proposed photoinduced LMCT promotes the reverse thiophene elimination from <b>2</b>. Finally, pressurizing solutions of <b>2 </b>with H<sub>2</sub> (150 psi) at 80 °C leads to the hydrodesulfurization of thiophene to give the Ti(IV) sulfide (<sup>Ket</sup>guan)(Im<sup>Dipp</sup>N)Ti(S) (<b>3</b>) and butane. </p>

Direct and Selective Synthesis of Adipic and Other Dicarboxylic Acids by Palladium‐Catalyzed Carbonylation of Allylic Alcohols

2020 ◽  
Vol 59 (46) ◽  
pp. 20394-20398
Author(s):  
Ji Yang ◽  
Jiawang Liu ◽  
Yao Ge ◽  
Weiheng Huang ◽  
Helfried Neumann ◽  
...  
Keyword(s):  
Dicarboxylic Acids ◽  
Allylic Alcohols ◽  
Selective Synthesis ◽  
Palladium Catalyzed
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