Copper‐in‐Charcoal (Cu/C): Heterogeneous, Copper‐Catalyzed Asymmetric Hydrosilylations

Abstract

Asymmetrische Kupferchemie …︁ heterogen durchgeführt? Ja, es geht: Der leicht herstellbare Katalysator Kupfer‐in‐Aktivkohle (Cu/C) wird problemlos in situ in eine nichtracemisch ligierte Kupferhydrid‐Form überführt, die asymmetrische Hydrosilylierungen bewirkt.

Polishing a Diamond in the Rough: “CuH” Catalysis with Silanes

“…Complementary to this homogeneous “CuH in a bottle”, Lipshutz et al. recently presented a heterogeneous catalyst for a variety of asymmetric reductions 26b. Copper(II) immobilized on charcoal, that is, copper‐in‐charcoal, was employed as a precatalyst in combination with a small amount of L5 ( 29 → 30 , Scheme 13).…”

Near‐Monodisperse Tetrahedral Rhodium Nanoparticles on Charcoal: The Shape‐Dependent Catalytic Hydrogenation of Arenes

“…Moreover, these heterogeneous systems are promising industrial catalysts. For example, commercially available Pd/C is frequently used in debenzylation, hydrogenation, and CC bond‐formation reactions in the laboratory and is also used in industry,1 and Ni/C,2 Cu/C,3 and Co/C4 have recently been developed as catalysts for coupling, hydrosilylation, and cycloaddition reactions, respectively.…”

Copper(II)‐Catalyzed Hydrosilylation of Ketones Using Chiral Dipyridylphosphane Ligands: Highly Enantioselective Synthesis of Valuable Alcohols

“…A significant breakthrough was accomplished by Lipshutz et al in 2001, [13b-d] whereby an especially active Cu I Cl/diphosphane (e.g., 3,5-xyl-MeO-BIPHEP [16] or DTBM-SEGPHOS [17] )/tBuONa catalyst system was developed to effect highly enantioselective hydrosilylation of a broad assortment of prochiral ketones, [18] with substrate-to-ligand molar ratios (S/L) of up to 100 000. Since then, a variety of effective copper catalysts that derive from enantiomerically pure diphosphanes (such as BINAP, DTBM-SEGPHOS or MeO-BIPHEP derivatives) and CuA C H T U N G T R E N N U N G (OAc) 2 ·H 2 O, [21] [CuFA C H T U N G T R E N N U N G (PPh 3 ) 3 ·2MeOH], [22] CuCl [23] or some heterogeneous copper sources, [24] have been applied in the relevant hydrosilylation reactions. Since then, a variety of effective copper catalysts that derive from enantiomerically pure diphosphanes (such as BINAP, DTBM-SEGPHOS or MeO-BIPHEP derivatives) and CuA C H T U N G T R E N N U N G (OAc) 2 ·H 2 O, [21] [CuFA C H T U N G T R E N N U N G (PPh 3 ) 3 ·2MeOH], [22] CuCl [23] or some heterogeneous copper sources, [24] have been applied in the relevant hydrosilylation reactions.…”

“…Concomitant with Lipshutzs work in 2001, Riant and coworkers [19] disclosed an air-accelerated and base-free CuF 2 / BINAP [20] /PhSiH 3 system that catalyzed the reduction of some alkyl aryl ketones with moderate to excellent enantioselectivities. Since then, a variety of effective copper catalysts that derive from enantiomerically pure diphosphanes (such as BINAP, DTBM-SEGPHOS or MeO-BIPHEP derivatives) and CuA C H T U N G T R E N N U N G (OAc) 2 ·H 2 O, [21] [CuFA C H T U N G T R E N N U N G (PPh 3 ) 3 ·2MeOH], [22] CuCl [23] or some heterogeneous copper sources, [24] have been applied in the relevant hydrosilylation reactions. Additionally, some efficient copper catalysts bearing chiral monophosphane [25] or tetraoxazoline [26] ligands have also been developed for the hydrosilylation of simple ketones.…”