Synthesis of fluoroalkyl-derivatised BINAP ligands

Ruthenium-catalysed asymmetric hydrogenation with fluoroalkylated BINAP ligands in supercritical CO2

“…However, the apolarity of scCO 2 restricts the application of many, "conventional", metal-based catalysts, in particular, those that contain chiral ligands, which are generally more complex in structure and, hence, more difficult to render soluble in scCO 2 . The introduction of perfluoroalkyl substituents, colloquially called "fluorous ponytails", can enhance ligand and catalyst solubilities in scCO 2 , and we have developed simple and efficient catalytic methods for the synthesis of a series of fluoroalkylated binaphthyl-based chiral ligands (Scheme 1) [5][6][7], including preliminary data on the ruthenium-catalysed hydrogenation of dimethyl itaconate in MeOH using 2 and 3 [5].…”

Pd-Catalyzed Mizoroki-Heck Reactions Using Fluorine-Containing Agents as the Cross-Coupling Partners

“…Purification of 75 by flash chromatography allowed easy reduction of the C=C double bonds of 75 under the standard Pd/C-or Rh/C-catalyzed hydrogenation conditions [69]. This method was successfully applied to the synthesis of binaphathols bearing fluorinated ponytails, which are potential ligands for catalysis in scCO2 and fluorous solvents [69,70]. The application of these ligands in the ruthenium-catalyzed hydrogenation of dimethyl itaconate revealed that the fluorous ponytails on the ligands imposed significant effects on the hydrogenation activity, but not on the enantioselectivity [70].…”

“…This method was successfully applied to the synthesis of binaphathols bearing fluorinated ponytails, which are potential ligands for catalysis in scCO2 and fluorous solvents [69,70]. The application of these ligands in the ruthenium-catalyzed hydrogenation of dimethyl itaconate revealed that the fluorous ponytails on the ligands imposed significant effects on the hydrogenation activity, but not on the enantioselectivity [70]. Later, Cai and co-worker developed a PCP Pincer-Pd catalyst (77), which was favorably used in Mizoroki-Heck cross-couplings between perfluoroalkyl alkenes (74) and aryl halides (78) for the preparation of perfluoroalkenylated aryl compounds (79) (Scheme 15) [71].…”

Repetitive Application of a Fluorous Chiral BINAP–Ru Complex in the Asymmetric Hydrogenation of Olefins

“…[15] Amongst the variety of examples for modified BI-NAP were reports of BINAP ligands bearing perfluoroalkyl tails, which allowed their employment in FBS as well as their use in supercritical carbon dioxide as a reaction medium. [7,[16][17][18] However, to the best of our knowledge, there exists no example for the successful recovery and reuse of a perfluorinated BINAP-metal complex. Hope et al [18] have reported the application of a lightly perfluorinated BINAP in the ruthenium-catalysed asymmetric hydrogenation of ketones, where an attempt was made to recover the catalytic entity by filtration through FSG.…”