Separation, recovery and recycling of a fluorous-tagged nickel catalyst using fluorous solid-phase extractionElectronic supplementary information (ESI) available: experimental details. See http://www.rsc.org/suppdata/cc/b3/b308543k/

Abstract

Highly efficient separation, recovery and recycling of the fluorous-tagged catalyst, [Ni[F13C6C(O)CHC(O)C6F13]2], can be achieved with fluorous solid-phase extraction, after the Lewis acid catalysed synthesis of enaminodiones in conventional organic solvents.

Recycling of a perfluoroalkylated BINOL ligand using fluorous solid-phase extraction

“…From 1 H and 119 Sn{ 1 H} NMR spectroscopic studies of this material, it is believed that a non-polar, R f6 -BINOL-Sn polymer is also formed in this system and this accounts for the ability to isolate the organic product without R f6 -BINOL contamination in contrast to our earlier work on the asymmetric alkylation of benzaldehyde with diethylzinc. When the isolated material was dried and reused in a second catalytic run with fresh aliquots of Ti(O i Pr) 4 , benzaldehyde and allyltri-n-butyltin, only unreacted starting materials were recovered. However, it is possible to recover (R)-R f6 -BINOL from the R f6 -BINOL-Sn polymer by hydrolysis with 4 M hydrochloric acid and this recovered (R)-R f6 -BINOL ligand was then reused in three further catalytic runs ( Table 4).…”

“…Optical rotation measurements were obtained using a Perkin Elmer Polarimeter 341 at 589 nm using a Na-Hal lamp. Ti( i OPr) 4 was obtained from a commercial source (Aldrich), while the BINOL ligands were either purchased from a commercial source (Fluka) or synthesised by literature methods. 5 Fluoroflash1 silica gel (40 mm) was purchased from Fluorous Technologies.…”

“…A solution of Ti(O i Pr) 4 (157 ml, 0.32 mmol) and BINOL (0.21 mmol, 0.2 equiv.) in dichloromethane (10 ml) was stirred for one hour.…”

“…in dichloromethane (10 ml) was stirred for one hour. An additional portion of Ti(O i Pr) 4 was then added (314 ml, 0.64 mmol) as well as the benzaldehyde (107 ml, 1.2 mmol). The solution was then cooled to 220 uC before adding diethylzinc (3.12 mmol, 3.12 ml of 1 M solution in hexane).…”

“…Recently, we reported the first example of separation, recovery and recycle of a perfluoroalkylated Lewis acid catalyst, [Ni{C 6 F 13 C(O)CHC(O)C 6 F 13 } 2 ], using FRP silica gel after catalyzing the reaction between 2,4-pentanedione and ethylcyanoformate in dichloromethane. 4 We have also extended the applications of this novel separation technique in order to recover and recycle lightly fluorinated BINAP ligands after the ruthenium-catalysed asymmetric hydrogenation of methyl acetoacetate. 5 Here, we demonstrate the efficient separation and recycle of a perfluoroalkylated BINOL ligand using fluorous solid-phase extraction.…”