Nondirecting Group sp³ C−H Activation for Synthesis of Bibenzyls via Homo‐coupling as Catalyzed by Reduced Graphene Oxide Supported PtPd@Pt Porous Nanospheres

Abstract

The use of heterogeneous bimetallic Pd-based nanocatalyst for directing the inactivated sp 3 CÀH coupling has been scarcely explored. This work reported the formation of symmetrical CÀC bonds from the inactivated sp 3 CÀH bonds catalyzed by employing reduced graphene oxide supported PtPd@Pt porous nanospheres. The reaction of sp 3 CÀH activation proceeded under mild conditions without any solvent, ligand or directing group. It is a higher atom-, step-and cost-effectiveness strategy for developing heterogeneous catalysts in the synthesis of bibenzyls with various functional groups (e. g. aryl, alkyl, methoxyl, halogen, ester, and pyridyl).

C(sp3)−C(sp3) bond formation via nickel-catalyzed deoxygenative homo-coupling of aldehydes/ketones mediated by hydrazine

“…Although the reductions of diarylalkenes and diarylalkynes provide means for the preparation of bibenzyl compounds 13 , 14 , homo-coupling strategies show superiority to access these compounds. For example, the homo-coupling of benzyl halides 15 , benzylmagnesium halides 16 , phenylacetic acids 17 , benzyl boronic acids 18 and methylbenzene derivatives 19 have been disclosed in recent years. However, these methods suffered from several drawbacks such as the tedious prefunctionalization steps, the use of moisture-sensitive organometallic reagents and the requirement of noble metals, which greatly limit their broad applicability.…”

Coupling photocatalytic water oxidation with organic reduction: strategy for using water to reduce organic molecules

“…In order to obtain a good result, we had to modify the photocatalyst, and found that the yield increased from 4% to 11% when Pd/g-C 3 N 4 was irradiated for 5 min in the presence of Na 2 CO 3 and water. These results indicate that the irradiating process can enhance the catalytic ability of Pd/g-C 3 N 4 , which is possibly due to that Pd 0 is the catalytically active species [47][48][49] , and such a process can result in an increase in the ratio of Pd 0 to Pd 2+ based on the characterization of catalyst. In addition, we observed the formation of hydrogen gas from the proton reduction that was unbeneficial for the reductive coupling, urging us to add a base to inhibit this competing reaction.…”

“…However, it is desired to overcome this problem because a new use of water as the green reducing agent to enable the reductive transformations of organic substances can be developed by this way. In addition, the reductive coupling of aryl or alkyl halides is of great significance in modern organic synthesis [47][48][49][50][51][52][53][54][55][56] , which has prompted us to select this kind of reaction as the model reaction to make our idea come true. Encouraged by prior success in applying carbon nitride-supported transition metal (M/g-C 3 N 4 ) into photocatalytic water splitting, [57][58][59][60][61][62][63][64][65] we selected this kind of semiconductor to achieve our goals.…”

Graphene oxide‐catalyzed CSp3–H activation of methylarenes in aqueous medium: A unified metal‐free access to amides and benzimidazoles

“…Furthermore, the benzylic C−H bond in toluene is more feeble than arene C−H, which shows remarkable selectivity for C Sp3 –H activation over C Sp2 –H activation. Recently, the activation of C Sp3 –H bond of methylarenes for C–C and C–hetero bonds formation has received considerable attention . Few synthetic protocols have been reported for the formation of amides using methylarenes and amines, which would be a significant complement to the traditional C–N forming strategies (Scheme b) .…”