Photoinduced Heterogeneous C−H Arylation by a Reusable Hybrid Copper Catalyst

Abstract

Heterogeneous copper catalysis enabled photoinduced C−H arylations under exceedingly mild conditions at room temperature. The versatile hybrid copper catalyst provided step‐economical access to arylated heteroarenes, terpenes and alkaloid natural products with various aryl halides. The hybrid copper catalyst could be reused without significant loss of catalytic efficacy. Detailed studies in terms of TEM, HRTEM and XPS analysis of the hybrid copper catalyst, among others, supported its outstanding stability and reusability.

Recyclable Ruthenium Catalyst for Distal meta‐C−H Activation

“…[14] Thereby,n umerous heterogenized homogeneous catalysts, namely hybrid catalysts, have been devised particularly by Jones [15] and Sawamura [16] among others. [17] In sharpc ontrast to this advance in hybrid catalysis, recyclable polymer-based [18] hybrid-ruthenium catalystf or remote CÀHa lkylations via s-activation has as of yet unfortunately proven elusive. Within our program on sustainable CÀHa ctivation, [19] we have now unraveled an unprecedented recyclable hybridruthenium catalyst for remote CÀHa lkylationsinabiomass-derived solvent, [20] on whichw er eport herein (Figure1b).…”

“…While classical heterogeneous catalysts—metal catalysts dispersed on solid surfaces—have been previously reported for C−H functionalizations, [12] hybrid catalysts [13] —homogeneous catalysts immobilized with organic linkers on solid supports—add unique properties to the design of the reusable catalysts [14] . Thereby, numerous heterogenized homogeneous catalysts, namely hybrid catalysts, have been devised particularly by Jones [15] and Sawamura [16] among others [17] . In sharp contrast to this advance in hybrid catalysis, recyclable polymer‐based [18] hybrid‐ruthenium catalyst for remote C−H alkylations via σ‐activation has as of yet unfortunately proven elusive.…”

Green strategies for transition metal-catalyzed C–H activation in molecular syntheses

“…70 Very recently, Ackermann achieved heterogeneous photoinduced copper-catalyzed C-H arylation of heteroarenes 54, 59 with aryl iodides 45 at room temperature (Scheme 20). 71 This photo-catalysis strategy proved to be highly robust leading to minimal leaching and enabling the recycling of the catalyst without loss of its efficiency.…”

A green approach for the synthesis of 2-substituted benzoxazoles and benzothiazoles via coupling/cyclization reactions

“…GC-MS (EI, 70 eV) m/z: 51, 63, 77, 90, 102, 112, 127, 140, 153 182, 194, 210, 225. 2-(4-Chlorophenyl)benzoxazole (3d) (Sirgamalla et al, 2020;Tang et al, 2020;Yang, 2020;Zhou et al, 2020) White solid, mp ¼ 146-147 C 50, 63, 75, 92, 100, 111, 137, 166, 194, 201, 209, 229. 2-Phenylbenzothiazole (3e) (Choi et al, 2020;Zhang et al, 2019) White solid, mp ¼ 124-125 C 1 H NMR (500 MHz, CDCl 3 ): δ ¼ 8.12-8.08 (m, 3H), 7.91 (d, J ¼ 8.0 Hz, 1H), 7. 51-7.48 (m, 4H), 7.40-7.37 (m, 1H).…”

“…GC-MS (EI, 70 eV) m/z: 51, 58, 69, 82, 92, 108, 121, 139, 152, 167, 184, 196, 211. 2-(4-Methoxyphenyl)benzothiazole (3f) (Choi et al, 2020;Zhang et al, 2019) White solid, mp ¼ 123-124 C 1 H NMR (500 MHz, CDCl 3 ): δ ¼ 8. 3H),7.88 (d,J ¼ 8.0 Hz,1H),1H),1H), 7.00 (dt, J ¼ 3.0 Hz, 9.0 Hz, 2H), 3.89 (s, 3H).…”