“In situ immobilization” of a multicomponent chiral catalyst (MCC) via non-covalent interactions for heterogeneous asymmetric hydrogenation reactions

Abstract

Novel hybrid catalysts that resulted from the anchoring of pyrene-tagged Rh(i) complexes onto graphene materials via π–π stacking interactions show excellent catalytic activity towards the hydrogenation of dehydroamino acid.

Chiral Graphene Hybrid Materials: Structures, Properties, and Chiral Applications

“…developed a “in situ immobilization” strategy for immobilizing Rh complex on graphene. [ 205 ] Pyrene‐tagged, multicomponent chiral catalysts were anchored on graphene via π – π stacking interaction. As illustrated in Figure , the chiral catalyst containing pyrene units was adsorbed onto graphene through π – π interaction between the pyrene units and graphene layers.…”

“…Moreover, the catalyst can be easily recycled without leaching toxic metal ions into the products. [ 205 ]…”

“…Graphene provides an excellent platform for creating new catalysts due to its 2D architecture and unique electrochemical properties. Among the chiral building blocks for constructing graphene based chiral material systems summarized in Section 2, proline, [ 41,43,53,58 ] enzymes, [ 145 ] and metal complexes [ 195–200,202,205–208 ] have become the most extensively used chiral species for developing chiral hybrid catalysts. To better address the issues, at this point, organocatalysis should be remarked first.…”

“…[ 58 ] Relative to proline, chiral metal complexes offer more possibilities. They can be adopted to perform a wider range of asymmetric reactions, e.g., olefin oxidation (with Mn complex), [ 195 ] olefin epoxidation (Mn complex), [ 196–200 ] sulfoxidation (Ti complex), [ 202 ] hydrogenation (Rh complex, [ 205 ] Ni complex, [ 207 ] and Pd complex [ 208 ] ), and ketone transfer hydrogenation (Ru complex). [ 206 ] The metal complex catalysts and the corresponding asymmetric reactions are summarized in Table 6.…”

Chiral Chromium Salen@rGO as Multipurpose and Recyclable Heterogeneous Catalyst

“…In contrast, this immobilization strategy has been much less developed in the context of asymmetric catalysis, with only four examples reported, to our knowledge. In the field of Rh‐promoted asymmetric hydrogenation, chiral phosphine‐containing catalysts have been deposited on CNT, [11] or assembled onto rGO [12] . We have immobilized copper bis(oxazoline) complexes for the enantioselective formation of C−C bonds, [13] and more recently, the noncovalent immobilization of Rh complexes was reported for the asymmetric hydroformylation and implemented in a flow mode [14] .…”