Ru-Catalyzed Deoxygenative Functionalization of Phenols via π-Coordination Activation: Mechanochemical Access to N-Aryl Amides and α-Aryl Carbonyls.

Given the vast occurrence and availability of both primary amides and phenols, the synthesis of N-aryl amides via direct coupling between these starting materials would be much attractive. Herein, we report an efficient method for the mechanochemical synthesis of N-aryl amides via ruthenium-catalyzed direct amidation of unprotected phenols with primary amides with water as the sole byproduct. Unexpectedly, replacing amides with methyl carboxylic acids, esters, or ketones, the same reaction led to the formation of α-aryl carbonyl derivatives instead of the anticipated aryl carboxylates.

Mechanochemical Sequential Deoxygenative Cross-Coupling Reactions of Phenols Under Ruthenium-Nickel Catalysis.

Herein, we report the first mechanochemical strategy for the Ru-catalyzed deoxygenative borylation of free phenols via C-O bond cleavage. This Ru-catalyzed phenolic borylation approach has been successfully extended to the Suzuki-Miyaura-type cross-coupling of phenols with aryl bromides. The protocol accepts a wide scope of phenolic substrates, allowing the synthesis of aryl pinacolboranes and biphenyl structures in excellent yields and serving as a better alternative to classical cross-coupling reactions in the context of pot, atom, and step economy synthesis.

Ruthenium Catalyzed Mechanochemical Transformation of Sulfonamide Group to Fluoro, Trifluoromethyl, and Trifluoromethoxy Functionalities.

A convenient route for the mechanochemical synthesis of fluorinated aromatic compounds, that is, fluoro, trifluoromethyl, and trifluoromethoxy arenes, has been developed via pyrylium tetrafluoroborate (Pyry-BF)-mediated desulfonamidative cross-coupling of primary sulfonamides under the synergy of a piezoelectric material BaTiO, and Ru-catalysis. This is the first-ever report on the selective transformation of sulfonamide (SONH) functionality to CF/OCF/F group in a single step under mechanochemical ball-milling conditions. Considering the importance of primary sulfonamides as the valuable pharmacophores, the present desulfonamidative cross-coupling approach could have potential to get synthetic utility in pharmaceutical industries for the late-stage functionalization of sulfonamide drugs and related active pharmaceutical ingredients (APIs).