Z-Selective Addition of Diaryl Phosphine Oxides to Alkynes via Photoredox Catalysis

ACS Catalysis ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 10599-10605 ◽  
Author(s):  
Huamin Wang ◽  
Yongli Li ◽  
Zilu Tang ◽  
Shengchun Wang ◽  
Heng Zhang ◽  
...  
Keyword(s):  
Phosphine Oxides ◽  
Photoredox Catalysis ◽  
Selective Addition

Modified Proline Auxiliaries for Selective Addition of Organocerium Reagents to Hydrazones

Synlett ◽  
1989 ◽  
Vol 1989 (01) ◽  
pp. 20-22 ◽  
Author(s):  
Theodor Weber ◽  
James P. Edwards ◽  
Scott E. Denmark
Keyword(s):  
Selective Addition

Spin-Forbidden Excitation Enables Infrared Photoredox Catalysis

2020 ◽  
Author(s):  
Tomislav Rovis ◽  
Benjamin D. Ravetz ◽  
Nicholas E. S. Tay ◽  
Candice Joe ◽  
Melda Sezen-Edmonds ◽  
...  
Keyword(s):  
Excited State ◽  
Ground State ◽  
Intersystem Crossing ◽  
Photoredox Catalysis ◽  
Infrared Irradiation ◽  
Triplet Excitation ◽  
New Family ◽  
Ir Light

We describe a new family of catalysts that undergo direct ground state singlet to excited state triplet excitation with IR light, leading to photoredox catalysis without the energy waste associated with intersystem crossing. The finding allows a mole scale reaction in batch using infrared irradiation.

Generation of Phosphoranyl Radicals via Photoredox Catalysis Enables Voltage–Independent Activation of Strong C–O Bonds

2018 ◽  
Author(s):  
Erin Stache ◽  
Alyssa B. Ertel ◽  
Tomislav Rovis ◽  
Abigail G. Doyle
Keyword(s):  
Carboxylic Acids ◽  
Functional Groups ◽  
Single Step ◽  
Direct Access ◽  
Photoredox Catalysis ◽  
Acyl Radical ◽  
Synthetic Strategy ◽  
Acyl Radicals ◽  
Benzyl Radicals ◽  
Aliphatic Carboxylic Acids

Alcohols and carboxylic acids are ubiquitous functional groups found in organic molecules that could serve as radical precursors, but C–O bonds remain difficult to activate. We report a synthetic strategy for direct access to both alkyl and acyl radicals from these ubiquitous functional groups via photoredox catalysis. This method exploits the unique reactivity of phosphoranyl radicals, generated from a polar/SET crossover between a phosphine radical cation and an oxygen centered nucleophile. We first show the desired reactivity in the reduction of benzylic alcohols to the corresponding benzyl radicals with terminal H-atom trapping to afford the deoxygenated product. Using the same method, we demonstrate access to synthetically versatile acyl radicals which enables the reduction of aromatic and aliphatic carboxylic acids to the corresponding aldehydes with exceptional chemoselectivity. This protocol also transforms carboxylic acids to heterocycles and cyclic ketones via intramolecular acyl radical cyclizations to forge new C–O, C–N and C–C bonds in a single step.

Regioselective C3-H Trifluoromethylation of 2H-Indazole Under Transition-Metal-Free Photoredox Catalysis

2019 ◽  
Author(s):  
Arumugavel Murugan ◽  
Venkata Nagarjuna Babu ◽  
Nagaraj Sabarinathan ◽  
Sharada Duddu. S
Keyword(s):  
Transition Metal ◽  
Visible Light ◽  
Practical Approach ◽  
Hypervalent Iodine ◽  
Radical Mechanism ◽  
Photoredox Catalysis ◽  
Metal Free

Here we report a visible-light-promoted metal-free regioselective C3-H trifluoromehtylation reaction that proceeds via radical mechanism and which supported by control experiments. The combination of photoredox catalysis and hypervalent iodine reagent provides a practical approach for the present trifluoromethylation reaction and synthesis of a library of trifluoromethylated indazoles.

Synthesis and Solid-State Structure of (4-Hydroxy-3,5-diiodophenyl)phosphine Oxides. Dimeric Motifs with the Assistance of O-H···O=P Hydrogen Bonds

2015 ◽  
Vol 19 (5) ◽  
pp. 469-474 ◽  
Author(s):  
Nicholas Bewick ◽  
Agata Arendt ◽  
Yan Li ◽  
S.awomir Szafert ◽  
Tadeusz Lis ◽  
...  
Keyword(s):  
Solid State ◽  
Hydrogen Bonds ◽  
Phosphine Oxides ◽  
State Structure ◽  
Solid State Structure

Highly Efficient and Selective Addition of Hydroxylamine to Nitriles in Ionic Liquids

2014 ◽  
Vol 11 (5) ◽  
pp. 751-756 ◽  
Author(s):  
Attila Voros ◽  
Zoltan Baan ◽  
Geza Timari ◽  
Istvan Hermecz ◽  
Peter Mizsey ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Highly Efficient ◽  
Selective Addition

Formal Total Syntheses of Crocacin A-D

2005 ◽  
Vol 70 (10) ◽  
pp. 1696-1708 ◽  
Author(s):  
Magnus Besev ◽  
Christof Brehm ◽  
Alois Fürstner
Keyword(s):  
Natural Products ◽  
Aldol Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Total Syntheses ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
The Common ◽  
Selective Addition

A concise route to the common polyketide fragment5of crocacin A-D (1-4) is presented which has previously been converted into all members of this fungicidal and cytotoxic family of dipeptidic natural products by various means. Our synthesis features asyn-selective titanium aldol reaction controlled by a valinol-derived auxiliary, a zinc-mediated, palladium-catalyzedanti-selective addition of propargyl mesylate10to the chiral aldehyde9, as well as a comparison of palladium-catalyzed Stille and Suzuki cross-coupling reactions for the formation of the diene moiety of the target.

scholarly journals Microwaves as “Co-Catalysts” or as Substitute for Catalysts in Organophosphorus Chemistry

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1196
Author(s):  
György Keglevich
Keyword(s):  
Coupling Reaction ◽  
Diels Alder ◽  
Typical Case ◽  
Conventional Heating ◽  
Phosphine Oxides ◽  
Phosphonic Acids ◽  
Co Catalysts ◽  
Mw Irradiation ◽  
Organophosphorus Chemistry ◽  
Hydrolysis Of

The purpose of this review is to summarize the importance of microwave (MW) irradiation as a kind of catalyst in organophosphorus chemistry. Slow or reluctant reactions, such as the Diels-Alder cycloaddition or an inverse-Wittig type reaction, may be performed efficiently under MW irradiation. The direct esterification of phosphinic and phosphonic acids, which is practically impossible on conventional heating, may be realized under MW conditions. Ionic liquid additives may promote further esterifications. The opposite reaction, the hydrolysis of P-esters, has also relevance among the MW-assisted transformations. A typical case is when the catalysts are substituted by MWs, which is exemplified by the reduction of phosphine oxides, and by the Kabachnik–Fields condensation affording α-aminophosphonic derivatives. Finally, the Hirao P–C coupling reaction may serve as an example, when the catalyst may be simplified under MW conditions. All of the examples discussed fulfill the expectations of green chemistry.

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