Carboxylate-Directed Addition of Aromatic C–H Bond to Aromatic Aldehydes under Ruthenium Catalysis

Abstract

We report that ruthenium complexes effectively catalyzed the carboxylate-directed addition of aromatic C−H bonds to aldehydes. The reactions of aromatic acids with a variety of aromatic aldehydes including unactivated ones proceeded efficiently to give the corresponding isobenzofuranone derivatives in high yields. The combination of ruthenium(II) complexes with tricyclohexylphosphine led to highly nucleophilic aryl−metal species, which enabled versatile [3 + 2] cycloaddition in the absence of a Lewis acid. This paper also demonstrates the application of supported ruthenium catalysts to the title reaction.

Ruthenium‐Catalyzed Synthesis of Isoindolinones via Amide‐Directed Addition of Aromatic C‐H Bonds to Aldimines

“…The addition of an aryl C‐H bond to N ‐tosyl aryl aldimine bearing two trifluoromethyl groups ( 2aa ) in the presence of [RuCl 2 ( p ‐cymene)] 2 together with a catalytic amount of NaHCO 3 in mesitylene at 170 °C for 3 h was investigated (Scheme ). Although we reported the efficient addition of aromatic acids to aldehydes to form isobenzofuranones under Ru catalysis, carboxylate was an unsuitable directing group for the present imine hydroarylation. The reactions of aromatic amides bearing a H, Ph, or 8‐quinolyl group on the N ‐atom gave the target products in quite low yields.…”

“…This reaction consists of the carboxylate‐directed nucleophilic addition of an aromatic C‐H bond to a carbonyl moiety to form a hydroxyl functionality under metal catalysis and subsequent intramolecular condensation with carboxylic acid, thus realizing the rapid construction of benzo‐fused O ‐heterocycles. Our group has recently reported the excellent performance of Ru catalysts in this reaction . On the other hand, imines often participate in such nucleophilic C‐C bond‐forming reactions as a carbon electrophile under the catalytic effects of a series of transition metals, such as Rh, Co, Mn and Y, to be converted into an amino functionality.…”

Preparation of Neutral trans - cis [Ru(O2CR)2P2(NN)], Cationic [Ru(O2CR)P2(NN)](O2CR) and Pincer [Ru(O2CR)(CNN)P2] (P = PPh3, P2 = diphosphine) Carboxylate Complexes and their Application in the Catalytic Carbonyl Compounds Reduction

“…These types of complexes can also promote alcohol dehydrogenation and the cycloisomerization of alkynols to five- to seven-membered endocyclic enol ethers . Ruthenium carboxylate catalysts have been found to activate C–H bonds, promote functionalization reactions, efficiently direct C–H/C–O bond arylations with phenols in water, and react with aldehydes . Ruthenium phosphine carboxylate complexes have been reported to catalyze the hydrogenation of carboxylic acids and their derivatives to alcohols, while the employment of BINAP-Ru­(II) dicarboxylates afforded the asymmetric hydrogenation of unsaturated carboxylic acids to the corresponding saturated products .…”

“…6 Ruthenium carboxylate catalysts have been found to activate C−H bonds, 7 promote functionalization reactions, 8 efficiently direct C−H/C−O bond arylations with phenols in water, 9 and react with aldehydes. 10 Ruthenium phosphine carboxylate complexes have been reported to catalyze the hydrogenation of carboxylic acids and their derivatives to alcohols, 11 while the employment of BINAP-Ru(II) dicarboxylates 12 afforded the asymmetric hydrogenation of unsaturated carboxylic acids to the corresponding s a t u r a t e d p r o d u c t s . 1 3 F u r t h e r m o r e , [ R u -(O 2 CR) 2 (CO) 2 (PPh 3 ) 2 ] (R = CH 2 OCH 3 , iPr, tBu, 2-cC 4 H 3 O, Ph) were successfully applied as catalysts in the addition of carboxylic acids to propargylic alcohols to give the corresponding β-oxo esters used in the pharma industry.…”

Palladium Catalyzed Regioselective Cyclization of Arylcarboxylic Acids via Radical Intermediates with Diaryliodonium Salts

“…To efficiently produce high value-added chemicals in a minimum of operations, it should be one of the ultimate goals for new methodology development . To this end, direct functionalization of ArCO 2 H is of particular interest with controllable site specificity for diversification of the parent aromatic nucleus by π-extension . Considering carboxylic acid as an excellent directing group in the synthesis, ortho -functionalization of ArCO 2 H is a widely employed strategy in metal-catalyzed installation of various substituents .…”