Cooperative Strategies for Catalytic Hydrogenation of Unsaturated Hydrocarbons

Abstract

This Perspective discusses catalytic hydrogenation reactions of alkenes, alkynes, and other unsaturated C−C substrates in which the catalyst design involves cooperative strategies that enable bifunctional H 2 activation and delivery. These approaches complement the more traditional use of single-site precious metal systems for such hydrogenation reactions in homogeneous catalysis. Strategies included in this Perspective are cooperation between (a) a catalytic metal site and a basic ligand residue, (b) a catalytic metal site and an acidic ligand residue, (c) frustrated acid/base pairs, and (d) two cocatalytic metal sites. Unique reactivity and selectivity patterns with nonprecious elements that have emerged from successful implementation of these strategies in catalytic transformations are emphasized.

Cooperative approaches in catalytic hydrogenation and dehydrogenation

“…MLC via ligands that feature a Lewis acid moiety is still an emerging area of (de)hydrogenation catalysis. 16 The importance of MLC pathways in stoichiometric (de)hydrogenation studies has been demonstrated frequently, [17][18][19][20][21] but this can be difficult to translate to catalytic regimes which are extremely challenging to study experimentally. Much of the…”

“…Within the realm of cooperative (de)hydrogenation catalysis, MLC systems are at the forefront, whereas MMC systems are relatively scarce. 6,9,16 This provides an opportunity to compare and contrast these two modes of cooperativity. As seen above, MLC strategies rely heavily on the presence of complementary acidic (e.g.…”

Cooperative Bond Activation and Facile Intramolecular Aryl Transfer of Nickel–Aluminum Pincer‐type Complexes

“…Incorporation of LA moieties into ligand frameworks has garnered interest for catalytic applications,where the LA can be another TM, [5] am ain group metal, [6] or lanthanide ion. [7] Ty pically,main group LAs act as s-acceptor ligands,engaging the TM in an inverse dative bond, or Z-type interaction.…”

Low-valent homobimetallic Rh complexes: influence of ligands on the structure and the intramolecular reactivity of Rh–H intermediates

“…The interest in homobimetallic catalysts has recently seen a renaissance 6. Selected catalytic applications include diazo-free cyclopropanation,7 small molecule activation,8,9 hydrogenation,10 hydroformylation11 and C–C coupling reactions 12. Notably, heterobimetallic complexes serve as models of the transmetallation step for the latter process 13–17.…”