Strain-Inducing Positional Alkene Isomerization

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(36), С. 20053 - 20061

Опубликована: Авг. 30, 2023

Small, strained ring systems are important pharmacophores in medicinal chemistry and versatile intermediates organic synthesis. However, the kinetic thermodynamic instability of many molecules renders them challenging to prepare. Here, we report a strain-inducing positional alkene isomerization reaction that provides mild selective access cyclobutene building blocks from readily obtained cyclobutylidene precursors. This endergonic relies on sequential synergistic action decatungstate polyanion photocatalyst cobaloxime co-catalyst store potential energy form strain. The versatility products is demonstrated through diverse subsequent strain-releasing transformations. Mechanistic studies reveal steric basis for strain-selective product formation.

Язык: Английский

---

Iridium-Catalyzed Migratory Terminal C(sp³)–H Amidation of Heteroatom-Substituted Internal Alkenes via Olefin Chain Walking

Journal of the American Chemical Society, Год журнала: 2023, Номер unknown

Опубликована: Окт. 31, 2023

Hydroamination facilitated by metal hydride catalysis is an appealing synthetic approach to access valuable nitrogen-containing compounds from readily available unsaturated hydrocarbons. While high regioselectivity can be achieved usually for substrates bearing polar chelation groups, the reaction involving simple alkenes frequently provides nonselective outcomes. Herein, we report iridium-catalyzed highly regioselective terminal C(sp3)-H amidation of internal utilizing dioxazolones as amino source via olefin chain walking. Most notably, this mechanistic motif double bond migration position operates not only with dialkyl-substituted including styrenes but also heteroatom-substituted olefins such enol ethers, vinyl silanes, and borons, thus representing first example methyl latter type through a nondissociative walking process.

Язык: Английский

---

Late-Stage Molecular Editing Enabled by Ketone Chain-Walking Isomerization

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(36), С. 19496 - 19502

Опубликована: Авг. 28, 2023

Herein, a method for the isomerization of ketones in manner akin to chain-walking reaction alkenes is described. Widely available and inexpensive pyrrolidine elemental sulfur are deployed as catalysts achieve this reversible transformation. Key utility approach was elucidation stereochemical model determine thermodynamically favored product kinetic selectivity observed. With distinct profile our ketone process, various steroids demonstrated rapidly access novel with "unnatural" oxidation patterns.

Язык: Английский

---

Photoinduced Pd‐Catalyzed Direct Sulfonylation of Allylic C–H Bonds

Angewandte Chemie International Edition, Год журнала: 2024, Номер 64(1)

Опубликована: Сен. 17, 2024

Allylic sulfones are valuable motifs due to their medicinal and biological significance versatile chemical reactivities. While direct allylic C-H sulfonylation represents a straightforward desirable approach, these methods primarily restricted terminal alkenes, leaving the engagement of internal counterparts formidable challenge. Herein we report photocatalytic approach that accommodates both cyclic acyclic alkenes with diverse substitution patterns electronic properties. Importantly, obtained can be readily diversified into wide range products, thus enabling formal alkene transposition all-carbon quaternary center formation through sequential functionalization.

Язык: Английский

---

Diastereoselective β-Hydroxy Vinylsulfone Isomerizations

Organic & Biomolecular Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

Vinylic phenylsulfones containing a β-hydroxyl stereocenter undergo diastereoselective isomerization to the corresponding allylic isomer upon treatment with 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU).

Язык: Английский

---