Synthesis of Dibenzo[c,e]oxepin‐5(7H)‐ones from Benzyl Thioethers and Carboxylic Acids: Rhodium‐Catalyzed Double CH Activation Controlled by Different Directing Groups

Abstract

A rhodium(III)-catalyzed cross-coupling of benzyl thioethers and aryl carboxylic acids through the two directing groups is reported. Useful structures with diverse substituents were efficiently synthesized in one step with the cleavage of four bonds (CH, CS, OH) and the formation of two bonds (CC, CO). The formed structure is the privileged core in natural products and bioactive molecules. This work highlights the power of using two different directing groups to enhance the selectivity of a double CH activation, the first of such examples in cross-oxidative coupling.

Oxidative C−H/C−H Cross‐Coupling Reactions between N‐Acylanilines and Benzamides Enabled by a Cp*‐Free RhCl3/TFA Catalytic System

“…Manipulating this strategy to access unsymmetric 2,2′‐difunctional biaryls is still a challenging task owing to the obstacles associated with achieving chemoselective cross‐coupling over homo‐coupling. In those pioneering studies, a significant excess of one substrate was required (usually 3–8 equiv) to increase the amount of the cross‐coupled product,,, which reduces the practicality of this strategy. Herein, we present the first completely regioselective oxidative C−H/C−H cross‐coupling reactions between N ‐acylanilines and benzamides with a Cp*‐free RhCl 3 /TFA catalytic system to forge 2‐amino‐2′‐carboxybiaryl scaffolds, even at a low molar ratio of the coupling partners (Scheme b).…”

Copper‐Catalyzed Reaction Cascade of Thiophenol Hydroxylation and S‐Arylation through Disulfide‐Directed C−H Activation

“…Subsequently, Shi and co‐workers reported the Rh‐catalyzed benzyl thioether C−H arylation using a combination of Cu(OAc) 2 (3 equiv) and a catalytic amount of AgOAc (0.3 equiv) as oxidant . More recently, the same group extended the strategy to the synthesis of biaryl compounds through benzyl thioether‐directed C−H activation and sequential condensation with benzylic acid . These pioneering works demonstrated the feasibility of thioether as the directing group.…”

Crystal structure of (2-bromobenzyl)((1-bromonaphthalen-2-yl)methyl)sulfane, C18H14Br2S

“…Organosulfur compounds have received widespread attention because of their various applications in areas such as medicine, agriculture, materials and organic synthesis [5][6][7][8][9][10][11][12]. Most notably among these are thioethers (compounds containing C-S-C bonds), which have been often used as valuable precursors in organic synthesis [6], as ligands in organometallic chemistry [5,7] and in catalysis [8]. To our best knowledge, the crystal structures of the organosulfur compounds containing C-S-C bonds are less reported [9][10][11][12].…”