Metal-free radical difunctionalization of ethylene

Chem, Год журнала: 2022, Номер 9(2), С. 472 - 482

Опубликована: Ноя. 9, 2022

Язык: Английский

---

Cu/SaBox‐Catalyzed Photoinduced Coupling of Acylsilanes with Alkynes

Angewandte Chemie International Edition, Год журнала: 2022, Номер 62(5)

Опубликована: Дек. 5, 2022

The transition metal-catalyzed cross-coupling reaction with Fischer metal carbene intermediates bearing an electron-rich alkoxyl or siloxyl group remains a big challenge due to the lack of readily available corresponding precursors. Herein, we report coupling alkynes Fischer-type copper species α-siloxyl group, which could be in situ generated from acylsilanes catalytically under photoirradiation and redox-neutral conditions. side-arm modified bisoxazoline (SaBox) ligands prove crucial for this reaction, provides alkynyl alcohol high yields remarkable heterocycle tolerance broad substrate scope.

Язык: Английский

---

Trifluoromethylations of (Hetero)arenes and Polarized Alkenes Using Trifluoroacetic Anhydride under Photoredox Catalysis

Organic Letters, Год журнала: 2023, Номер 25(13), С. 2372 - 2376

Опубликована: Март 27, 2023

A novel trifluoromethylation of (hetero)arenes and polarized alkenes using simple trifluoroacetic anhydride (TFAA) as the low price CF3 source under photoredox catalysis was developed without additives such bases, hyperstoichiometric oxidant, or auxiliaries. The reaction showed excellent tolerance, including to some important natural products prodrugs, even on gram scale extended ketones. This protocol provides a practical utilization TFAA. Several perfluoroalkylations trifluoromethylation/cyclizations were successfully achieved identical conditions.

Язык: Английский

---

The Indenyl Effect: Accelerated C−H Amidation of Arenes via Ind*Rh^III Nitrene Transfer Catalysis**

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(23)

Опубликована: Апрель 6, 2023

Investigations into C-H amidation reactions catalysed by cationic half-sandwich d6 metal complexes revealed that the indenyl-derived catalyst [Ind*RhCl2 ]2 significantly accelerated directed ortho of benzoyl silanes using 1,4,2-dioxazol-5-ones. Ring slippage involving a haptotropic η5 to η3 rearrangement indenyl complex proposedly enables ligand substitution at centre proceed via associative, rather than dissociative pathways, leading significant rate and yield enhancements. Intriguingly, this phenomenon appears specific for weakly coordinating carbonyl-based directing groups with no acceleration observed corresponding strongly nitrogen-based groups.

Язык: Английский

---

Copper-Catalyzed 1,4-Trifluoromethylthio-Arylsulfonylation of 1,3-Enynes via the Insertion of Sulfur Dioxide

Organic Letters, Год журнала: 2023, Номер 25(31), С. 5916 - 5921

Опубликована: Июль 27, 2023

A copper-catalyzed trifluoromethylthio-arylsulfonylation between 1,3-enynes, AgSCF3, aryldiazonium tetrafluoroborates, and SO2 (from SOgen) is presented, which could introduce sulfone, SCF3, allene moieties into one molecule simultaneously. This strategy features mild reaction conditions, good substrate compatibility, excellent regioselectivity. The products obtained have the potential for further conversion other valuable compounds. Initial investigations mechanism suggest that it may proceed via a radical pathway. Notably, SOgen was proven as uniquely effective surrogate in this transformation.

Язык: Английский

---

Chemoselective Synthesis of Unsymmetrical Dithioacetals through Sequential Carbene Insertion and Acetal Exchange of Acylsilanes and Thiols under Visible Light Irradiation

Organic Letters, Год журнала: 2024, Номер 26(6), С. 1282 - 1286

Опубликована: Фев. 1, 2024

Dithioacetals are a frequently used motif in synthetic organic chemistry, and most existing reports discuss only symmetrical dithioacetals. Examples of unsymmetrical dithioacetals scarce, few general methods for the selective synthesis these compounds exists. An intriguing visible-light-induced strategy has been established this work sequential reactions S–H insertion acetal exchange between acylsilanes two different thiols that deliver wide variety moderate yields. The were obtained with high selectivity, great functional groups tolerated.

Язык: Английский

---

Stereoselective Synthesis of Silyl Enol Ethers with Acylsilanes and α,β-Unsaturated Ketones

Organic Letters, Год журнала: 2024, Номер 26(28), С. 5911 - 5916

Опубликована: Июль 8, 2024

Acylsilanes are emerging bench-stable reagents for the generation of electron-rich oxycarbenes that difficult to access with unstable diazo compounds. Herein, we report a siloxycarbene-mediated stereoselective synthesis silyl enol ethers through visible-light-induced intermolecular reactions between acylsilanes and α,β-unsaturated ketones. Both solvent low temperature important success reaction. This approach features atomic economics, exclusive stereocontrol, broad substrate scope. The synthetic potential this methodology is demonstrated by gram-scale reaction various downstream transformations including requiring configuration purity ethers.

Язык: Английский

---

Reductive Cyclopropanation through Bismuth Photocatalysis

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(32), С. 22140 - 22144

Опубликована: Авг. 5, 2024

We present here a catalytic method based on low-valent Bi complex capable of cyclopropanation double bonds under blue LED irradiation. The catalysis features various unusual Bi-based organometallic steps, namely, (1) two-electron inner sphere oxidative addition Bi(I) to CH2I2, (2) light-induced homolysis the Bi(III)–CH2I bond, (3) subsequent iodine abstraction-ring-closing, and (4) reduction Bi(III) with an external reducing agent close cycle. Stoichiometric experiments support proposed mechanism. This protocol represents unique example reductive photocatalytic process bismuth radical catalysis.

Язык: Английский

---

Thermally Activated Delayed Fluorescence Sensitizers As Organic and Green Alternatives in Energy-Transfer Photocatalysis

ACS Sustainable Chemistry & Engineering, Год журнала: 2022, Номер 10(30), С. 9665 - 9678

Опубликована: Июль 21, 2022

Photocatalysis has captured the imagination of synthetic chemists and is poised to become a staple fine chemical industry. Over past decade, subfield energy-transfer (EnT) catalysis expanded dramatically, harnessing excited states photosensitizer unlock variety redox-neutral, radical-based reactivities in mild selective fashion. However, many developments this discipline rely on precious rare earth metals such as iridium. This perspective will highlight rise thermally activated delayed fluorescence (TADF) materials metal-free alternatives EnT photocatalysis for organic transformations. Emphasis be placed recent progress cycloadditions, E/Z isomerization olefins, other radical-initiated processes; all mediated by mechanism Dexter energy transfer. The tunable excited-state energetics dynamics TADF allow them effectively compete with iridium-based sensitizers, indicating their promise green organocatalysis.

Язык: Английский

---

Cascade cyclization of alkene-tethered acylsilanes and allylic sulfones enabled by unproductive energy transfer photocatalysis

Nature Communications, Год журнала: 2022, Номер 13(1)

Опубликована: Окт. 16, 2022

Abstract Developing photo-induced cascade cyclization of alkene-tethered acylsilanes is challenging, because are unstable under light irradiation. Herein, we report that the energy transfer from excited to a photocatalyst possesses lower triplet can inhibit undesired decomposition acylsilanes. With neutral Eosin Y as photocatalyst, an efficient synthesis cyclopentanol derivatives achieved with and allylic sulfones. The reaction shows broad substrate scope synthetic potential this transformation highlighted by construction which contain fused-ring or bridged-ring.

Язык: Английский

---