The Journal of Organic Chemistry最新文献

A Ni/1-bpp catalyst was demonstrated to be effective in the Negishi alkylation with multiple classes of alkylpyridinium salts, including α-primary and α-secondary. These conditions are also effective for benzylic pyridinium salts, demonstrating the successful Negishi alkylation of benzylic pyridinium salts for the first time. Further, 14 derivatives of 1-bpp were prepared with a variety of steric and electronic properties to study how these changes impact the success of the Negishi alkylation.

In recent years, the "Escape-from-Flatland" trend has prompted the synthetic community to develop a set of cross-coupling strategies to introduce sp³-carbon-based fragments in organic compounds. This study presents a novel nickel-catalyzed electrochemical methodology for reductive cross-electrophile coupling. The method enables C(sp²)-C(sp³) linkages using inexpensive amine-derived radical precursors and aryl iodides. The use of electrochemistry as a power source reduces waste and avoids chemical reductants, making this approach a more sustainable alternative to traditional cross-coupling methods.

Direct C(sp²)-H bond functionalization of the tropone skeleton constitutes an atom-economical strategy to access substituted tropones that exist in some bioactive compounds. Herein, we report a convenient method for the preparation of 2-hydrazinotropones via C(sp²)-H bond functionalization. A variety of tropones participated in the dehydrogenative hydrazination reaction with hydrazine, delivering structurally diverse 2-hydrazinotropones in moderate to good yields with extremely high regioselectivity. This method is featured by operational simplicity and metal-free reaction conditions, thereby tolerating various functional groups.

Monofluoroalkene scaffolds are frequently found in various functional molecules. Herein, we report a Pd-IHept-catalyzed (NHC = N-heterocyclic carbene) defluorinative functionalization approach for the synthesis of monofluoroalkenes from gem-difluorocyclopropanes and malonates. The flexible yet sterically hindered N,N'-bis(2,6-di(4-heptyl)phenyl)imidazol-2-ylidene ligand plays a key role in ensuring the high reaction efficiency. In addition, sterically hindered 1,1- and 1,2-disubstituted gem-difluorocyclopropanes could also be used in this transformation.

We present a streamlined methodology that integrates regioselective tetrahalogen-BODIPY and o-hydroxyphenylboronic acid in a one-pot process, leveraging S_NAr nucleophilic substitution in conjunction with Suzuki coupling to afford diarenofuran [b]-fused BODIPYs (DBFB1-9) with commendable yields (85-95%) and short reaction times (0.5-1.0 h). X-ray structure analyses of DBFB5,7-9 elucidate that these diarenofuran[b]-fused BODIPYs adopt a "butterfly" conformation, maintaining a highly rigid planarity. A comprehensive examination of the spectroscopic and electrochemical properties of these diarenofuran[b]-fused BODIPY derivatives, incorporating various substituents, reveals intriguing characteristics, including pronounced absorption and emission in the near-infrared region (NIR), elevated fluorescence quantum yields (Φ_F = 75-89% in dichloromethane), and tunable HOMO-LUMO levels. Remarkably, compared to DBFB1-8, DBFB9 possesses a large extended π-conjugated system, resulting in significant red shifts in its absorption and emission maxima, reaching 623 and 635 nm, respectively, and a reduced HOMO-LUMO gap. Despite this substantial structural expansion, DBFB9 maintains a surprisingly high fluorescence quantum yield (Φ_F = 80%), underscoring its exceptional photophysical performance and strong potential for applications requiring efficient NIR emission and robust fluorescence retention.

Sodium triflinate (CF₃SO₂Na) is an inexpensive bench-stable radical CF₃ source that is often activated by external oxidants such as peroxides. However, despite the commercial accessibility of CF₃SO₂Na, the salt has never been applied to decarboxylative trifluoromethylation due to challenges in controlled cross-radical coupling. We report a redox-neutral approach to decarboxylative C(sp³) trifluoromethylation of carboxylic acid derivatives. Mechanistic inquiry is performed to address the limitations in scope.