Cp*Rh(iii) and Cp*Ir(iii)-catalysed redox-neutral C–H arylation with quinone diazides: quick and facile synthesis of arylated phenols

Abstract

Cp*Rh(III)- and Cp*Ir(III)-catalysed direct C-H arylation with quinone diazides as efficient coupling partners is disclosed. This redox-neutral protocol offers a facile, operationally simple and environmentally benign access to arylated phenols. The reaction represents the first example of Cp*Ir(III)-catalysed C-H direct arylation reaction.

Comparison of the Reactivities and Selectivities of Group 9 [Cp*MIII] Catalysts in C−H Functionalization Reactions

“…[31] A[ Cp*Rh III ]-catalyzed reaction of 2phenylpyridines with quinone diazides (1.5 equiv) provided monoarylated compounds as the major products, along with minor amounts of the bisarylated compounds (Scheme 22 a). [31] A[ Cp*Rh III ]-catalyzed reaction of 2phenylpyridines with quinone diazides (1.5 equiv) provided monoarylated compounds as the major products, along with minor amounts of the bisarylated compounds (Scheme 22 a).…”

“…An otable example of controlling the degree of CÀHf unctionalization (mono-versusb isarylation) was reportedb yL i, Wang, and co-workers. [31] A[ Cp*Rh III ]-catalyzed reaction of 2phenylpyridines with quinone diazides (1.5 equiv) provided monoarylated compounds as the major products, along with minor amounts of the bisarylated compounds (Scheme 22 a). In particular, when meta-substituted substrates were subjected to the optimized conditions, monoarylation took place almost exclusively at the sterically less-hinderedp osition.…”

Iridium(iii)-catalyzed regioselective direct arylation of sp2 C–H bonds with diaryliodonium salts

“…[9] In 2015, Wang and Li reported Cp*Ir(III)-catalyzed redox-neutral C-H arylation with quinone diazides to construct a series of arylated phenols. [10] Later, Chang et al uncovered Cp*Ir(III)catalyzed mild and broad C-H arylation of arenes with aryldiazonium salts. [11] Diaryliodonium salts are received tremndous attention in C-H activation field, [12] however, employing them as arylating reagents in Cp*Ir(III)-catalyzed reaction is still rare.…”

Divergent Coupling of Anilines and Enones by Integration of C−H Activation and Transfer Hydrogenation

“…[11] Furthermore,I r III catalysts are generally better players than Rh III catalysts in TH, possibly owing to the higher stability and reactivity of iridium hydrides. [11] Furthermore,I r III catalysts are generally better players than Rh III catalysts in TH, possibly owing to the higher stability and reactivity of iridium hydrides.…”

“…Thed ifference between iridium and rhodium catalysts in CÀHa ctivation has been documented. [11] Furthermore,I r III catalysts are generally better players than Rh III catalysts in TH, possibly owing to the higher stability and reactivity of iridium hydrides. [12] It was discovered that the Rh III -catalyzed coupling of PhNHPy and EVK proceeded at elevated temperature to give a Z/E mixture of the homoallylated product 6aa (78 %) in i PrOH in the presence of ac atalytic amount of Zn(OAc) 2 (Scheme 4).…”