Palladium(0) π-Lewis Base Catalysis: Concept and Development

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(10), С. 6422 - 6437

Опубликована: Март 1, 2024

The development of a new catalytic strategy plays vital role in modern organic chemistry since it permits bond formation an unprecedented and more efficient manner. Although the application preformed metal complexes as π-base-activated reagents have enabled diverse transformations elegantly, concept by directly utilizing transition metals π-Lewis base catalysts remain underdeveloped, especially field asymmetric catalysis. Here, we outline our perspective on discovery palladium(0) catalyst, which is capable increasing highest occupied molecular orbital (HOMO) energy both electron-neutral electron-deficient 1,3-dienes 1,3-enynes upon flexible η2-complexes formed situ resultant π-backdonation. Thus, fruitful carbon–carbon-forming reactions with electrophiles can be achieved enantioselectively vinylogous addition pattern, conceptually different from classical oxidative cyclization mechanism. Emphasis will given to mechanism elucidation, features, reaction design together further this emerging field.

Язык: Английский

---

Asymmetric Intramolecular Hydroamination to Construct Diverse N–N/C–N Indole Atropisomers via Cooperative Pd(0) and Chiral Phosphoric Acid Catalysis

Organic Letters, Год журнала: 2025, Номер unknown

Опубликована: Март 24, 2025

Here we present an enantioselective intramolecular hydroamination reaction of o-aminophenyl-1,3-enynes via cooperative catalysis Pd(0) and chiral phosphoric acid. This approach enables the efficient construction N–N/C–N axially stereogenic indoles with broad skeletal diversity high levels enantioselectivity in a completely atom-economic manner. Mechanistic studies indicate that protonation alkyne moiety π-Lewis base activation is favored, phosphate counteranion plays crucial role controlling atroposelectivity ring-closure step.

Язык: Английский

---

Enantioselective Cross-[4 + 2]-Cycloaddition/Decarboxylation of 2-Pyrones by Cooperative Catalysis of the Pd(0)/NHC Complex and Chiral Phosphoric Acid

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(10), С. 6936 - 6946

Опубликована: Фев. 28, 2024

Here, we describe a cooperative Pd(0)/chiral phosphoric acid catalytic system that allows us to realize the first chemo-, regio-, and enantioselective sequential cross-[4 + 2]-cycloaddition/decarboxylation reaction between 2-pyrones unactivated acyclic 1,3-dienes. The key success of this transformation is utilization an achiral N-heterocyclic carbene (NHC) as ligand newly developed chiral cocatalyst. Experimental investigations computational studies support idea Pd(0)/NHC complex acts π-Lewis base increase nucleophilicity 1,3-dienes via η2 coordination, while simultaneously increases electrophilicity by hydrogen bonding. By synergistic catalysis, 2]-cycloaddition decarboxylation proceeds efficiently, enabling preparation wide range vinyl-substituted 1,3-cyclohexadienes in good yields enantioselectivities. synthetic utility demonstrated transformations product various valuable six-membered carbocycles.

Язык: Английский

---

Chemodivergent Tandem Hydroalkylation and Hydroalkenoxylation of Conjugated Enynes

ACS Catalysis, Год журнала: 2024, Номер 14(13), С. 9742 - 9751

Опубликована: Июнь 14, 2024

Due to the instability and weak O-nucleophilicity of enol, carbonyl compounds prefer function as C-nucleophiles instead O-nucleophiles in extensively studied transition metal-catalyzed hydrofunctionalizations unsaturated bonds. The corresponding hydroalkenoxylation reaction has thus long been unexplored. Here, we describe a chemodivergent protocol for challenging reactions. Dictated by Pd catalyst bearing different ligands, both 5-exo-trig 6-endo-trig processes are demonstrated be feasible between 1,3-enynes ketoesters, polysubstituted hydrofurans hydropyrans achieved good yields excellent chemoselectivities. In addition, enantioselective is also explored under an Rh moderate efficiency but with high stereoselectivities. Mechanistic studies corroborate designed tandem hydroalkylation uncover that ligand-to-ligand hydrogen transfer process might involved turnover-limiting step hydroalkenoxylation.

Язык: Английский

---

Palladium-Catalyzed Divergent Synthesis from o-Sulfonamido Trifluoroacetophenones and 2-En-4-ynyl Carbonates

Organic Letters, Год журнала: 2025, Номер unknown

Опубликована: Фев. 15, 2025

Here we present a palladium-catalyzed divergent transformative reaction between o-sulfonamido trifluoroacetophenones and 2-en-4-ynyl carbonates. A spectrum of enantioenriched 2,5-dihydrofuran-fused tetrahydroquinolines bearing either (Z)- or (E)-exocyclic double bond are constructed with moderate to high enantioselectivity from 5-aryl-substituted carbonates by tuning palladium sources, while analogous 2,3-dihydrofuran-fused products furnished using 5-alkyl-substituted ones.

Язык: Английский

---

NHC and photoredox co-catalyzed 1,4-alkylcarbonylation of 1,3-enynes

Organic Chemistry Frontiers, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

A strategy to obtain 1,2-alkenyl ketone products by radical relay coupling is proposed.

Язык: Английский

---