Halogen Bonding Initiated Difunctionalization of [1.1.1]Propellane via Photoinduced Polarity Match Additions.

Bicyclo[1.1.1]pentane (BCP), recognized as a bioisostere for para-disubstituted benzene, has gained widespread interest in drug development due to its ability to enhance the physicochemical properties of pharmaceuticals. In this work, we introduce a photoinduced, halogen bonding-initiated, metal-free strategy for synthesizing various BCP derivatives. This method involves the generation of nucleophilic α-aminoalkyl radicals via halogen-bonding adducts. These undergo selective radical addition to [1.1.1]propellane, yielding electrophilic BCP radicals that subsequently participate in polarity-matched additions, culminating in the difunctionalization of bicyclopentane. The versatility and practicality of this metal-free approach are underscored by its broad substrate scope, which includes late-stage functionalization and a series of valuable transformations, all conducted under mild reaction conditions.

Electro-mechanochemical approach towards the chloro sulfoximidations of allenes under solvent-free conditions in a ball mill.

An electro-mechanochemical protocol for the synthesis of vinylic sulfoximines has been developed. Utilising mechanochemically strained BaTiO3 nanoparticles, the catalytic active system is generated in situ by the reduction of copper(II) chloride. Various combinations of electron-donating and -withdrawing groups are tolerated, and the approach leads to products with difunctionalised double bonds in good to excellent yields. Attempts to add a sulfoximidoyl chloride to an alkyne proved difficult. Additions of a sulfonyl iodide to allenes and alkynes proceeded smoothly in the presence of silica gel without the need for activation by a piezoelectric material.

Iron-Catalyzed Intramolecular Arene C(sp2 )-H Amidations under Mechanochemical Conditions.

In a ball mill, FeBr3 -catalyzed intramolecular amidations lead to 3,4-dihydro-2(1H)-quinolinones in good to almost quantitative yields. The reactions do not require a solvent and are easy to perform. No additional ligand is needed for the iron catalyst. Both 4-substituted aryl and ß-substituted dioxazolones provide products with high selectivity. Mechanistically, an electrophilic spirocyclization followed by C-C migration explains the formation of rearranged products.

Copper-Catalyzed, Aerobic Synthesis of NH-Sulfonimidamides from Primary Sulfinamides and Secondary Amines.

NH-Sulfonimidamides are prepared by copper-catalyzed coupling of primary sulfinamides with secondary amines. Neither a ligand nor an additive is needed, and air is the terminal oxidant. The reactions occur at room temperature, show good functional group tolerance, and lead to products in good yields. A sulfanenitrile is proposed as an intermediate in this oxidative amination.

The Preparation of Diaryl Sulfoxinium Triflates and Their Application in Palladium-Catalyzed Cross-Coupling Reactions.

Treatment of N-methyl-S,S-diaryl sulfoximines with methyl trifluoromethanesulfonate provides bench-stable sulfoxinium salts in excellent yields. Applying them in Sonogashira-, Heck- and Suzuki-type cross-coupling reactions leads to the corresponding products by sequential C-S bond cleavage and C-C bond formation. Electronic factors induced by substituents on the S-aryl groups govern the coupling efficiency.

Introduction of Lipophilic Side Chains to NH-Sulfoximines by Palladium Catalysis Under Blue Light Irradiation.

Palladium catalysis under blue (LED) light irradiation allows conversion of NH-sulfoximines into products with long lipophilic side chains attached to the S═N moiety. The three-component reactions involve both radicals and organometallic intermediates stemming from alkyl bromides and butadienes. The substrate scope is broad, and the products are formed in moderate to good yields.

Three-Dimensional Heterocycles by 5-exo-dig Cyclizations of S-Methyl-N-ynonylsulfoximines.

Upon treatment with Cs2CO3, S-methyl-N-ynonylsulfoximines undergo 5-exo-dig cyclizations to give three-dimensional heterocycles. The reactions proceed at ambient temperature with a wide range of substrates affording the corresponding products in good to excellent yields.

Synthesis of Benzothiadiazine-1-oxides by Rhodium-Catalyzed C-H Amidation/Cyclization.

A rhodium-catalyzed C-H amidation/cyclization sequence provides benzothiadiazine-1-oxides from sulfoximines and 1,4,2-dioxazol-5-ones in good yields. The reaction is characterized by a high functional group tolerance and, in contrast to most previous transformations of this type, is well-suited for S-alkyl-S-aryl-substituted sulfoximines.

CuH-Catalyzed Asymmetric Intramolecular Reductive Coupling of Allenes to Enones.

The CuH-catalyzed asymmetric intramolecular reductive coupling of allenes to enones is successfully realized, providing cis-hydrobenzofurans with promising yields and excellent enantioselectivities. Such brilliant enantioselectivities are partially contributed by CuH-catalyzed favorable kinetic resolution of the cyclization products. This protocol tolerates a broad range of functional groups, allowing for further construction of tricyclic and bridged-ring structures. Moreover, the meta-chiral functionalization of 4-substituted phenol and asymmetric dearomatization modification of phenol-contained bioactive molecules are also described.

Bisannulation of Benzamides and Cyclohexadienone-Tethered Allenes Triggered by Cp*Rh(III)-Catalyzed C-H Activation and Relay Ene Reaction.

The diastereoselective bisannulation of N-(pivaloyloxy)benzamides and cyclohexadienone-tethered allenes was accomplished through Cp*Rh(III)-catalyzed C-H activation and relay ene reaction, providing a 3-isoquinolonyl cis-hydrobenzofuran framework with high yields and diastereoselectivities. This reaction tolerates a wide range of functional groups, enabling further conversions to tricyclic and bridged-ring structures. Moreover, the dearomatization modification of phenol-contained bioactive molecule is also elaborated.