Transition-Metal-Free α-Arylation of Enolizable Aryl Ketones and Mechanistic Evidence for a Radical Process

Transition-Metal-Free Synthesis of Homo- and Hetero-1,2,4-Triaryl Benzenes by an Unexpected Base-Promoted Dearylative Pathway

An unprecedented approach for the synthesis of homo- and hetero-1,2,4-triaryl benzenes has been developed using a simple base-mediated reaction of either α-aryl cinnamyl alcohols or α,γ-di-aryl propanones. The salient feature of this strategy involves the sequential hydride transfer, regiospecific condensation, regiospecific dearylation, and aromatization under metal-free reaction conditions. The synthesis of unsymmetrically substituted triphenylenes by oxidative coupling of the synthesized 1,2,4-triaryl benzenes has also been demonstrated.

Enantioselective Oxidative Rearrangements with Chiral Hypervalent Iodine Reagents

A stereoselective hypervalent iodine‐promoted oxidative rearrangement of 1,1‐disubstituted alkenes has been developed. This practically simple protocol provides access to enantioenriched α‐arylated ketones without the use of transition metals from readily accessible alkenes.

Nickel catalyzed α-arylation of ketones with aryltrimethylammonium triflates

C(sp³)–C(sp²) coupling of aromatic ketones with a variety of aryltrimethylammonium triflates was performed in the presence of Ni(COD)₂, IPr·HCl, and LiOBu^t to yield α-arylated ketones in reasonable to excellent yields.

Cross-benzoin and Stetter-type reactions mediated by KOtBu-DMF via an electron-transfer process

The KOtBu-DMF system promotes benzoin- and Stetter-like reactions of alpha-diketone donors through a double electron-transfer-based mechanism.

Ligand-Mediated and Copper-Catalyzed C(sp(3))-H Bond Functionalization of Aryl Ketones with Sodium Sulfinates under Mild Conditions

A novel and convenient copper (II) bromide and 1,8-diazabicyclo[5.4.1]undec-7-ene (DBU) or 1,10-phenanthroline catalysis protocol for the construction of α-alkyl-β-keto sulfones via C(sp(3))-H bond functionalization followed by C(sp(3))-S bond formation between aryl ketones and sodium sulfinates at room temperature has been developed. This method is applicable to a wide range of aryl ketones and sodium sulfinates. The electronic effects of aryl ketones and ligands effects of the copper salts are crucial for this transformation. Typically, substituted aryl ketones with electron-withdrawing group do not need any ligand to give a good to excellent yield, while substituted aryl ketones with electron-donating group and electron-rich heteroaromatic ketones offer a good to excellent yield only under the nitrogen-based ligands. The practical value of this transformation highlights the efficient and robust one-pot synthesis of α-alkyl-β-keto sulfones.