Asymmetric hydrogenation of the CO bond with the recycling of an organometal catalyst deposited on a solid organic polyelectrolyte

Recyclable Stereoselective Catalysts

“…Vinodradov et al heterogenized the Ru-( S )-BINAP hydrogenation catalyst in a poly(diallyldimethylammonium salt). This heterogeneous catalyst was reused three times in methyl levulinate hydrogenation (S/C = 200, 40 atm H 2 ) affording the respective alcohol with excellent enantioselectivities (>98% ee) …”

“…This heterogeneous catalyst was reused three times in methyl levulinate hydrogenation (S/C ) 200, 40 atm H 2 ) affording the respective alcohol with excellent enantioselectivities (>98% ee). 94 Raja et al applied Rege method to physically trap several ionic complexes inside desiccant silicas having a narrow pore size distribution (Davison silica type). It was observed that the chiral restriction exerted by the support could induce or improve the enantioselectivity of rhodium-and palladiummediated R-ketoesteres hydrogenation compared with the reaction run in homogeneous media (as an example with catalyst 23, Scheme 9).…”

Ionic liquids as substrate-specific recoverable solvents and catalysts of regio-, stereo- and enantioselective organic reactions

“…99 The method of ionic immobilizing allows some organometal catalysts to be regenerated as well. 104 Implementation of the second approach resulted in the synthesis of a series of chiral pyrrolidine derivatives 43, 105 114 containing ionic groups, which efficiently catalysed asymmetric aldol reactions and Michael reactions in organic solvents, ionic liquids, and in some cases in water (Scheme 21). It should be noted that water, which is an available and environmentally friendly solvent, finds increasingly wide use in organic synthesis.…”