Synthesis of polymer/CNTs composites for the heterogeneous asymmetric hydrogenation of quinolines

Efficient Asymmetric Hydrogenation of Quinolines over Chiral Porous Polymers Integrated with Substrate Activation Sites

“…The FT-IR spectra of reused P-C-A 1.0 -RuOTf and P-C-A 1.0 -RuOTs were almost identical to the corresponding fresh ones with characteristic bands at 1163 and 1329 cm –1 assigned to TsO – (Figure c). The absence of the characteristic vibration of the C–F bond suggests the loss of TfO – for the used P-C-A 1.0 -RuOTf, which is consistent with our previous results . Nevertheless, the recycle stability of P-C-A 1.0 -RuOTf is improved, indicating that the leached TfO – group from VDPEN-RuOTf was supplemented by TsO – integrated in the polymer network.…”

“…The recycle stability of solid catalysts is of extreme importance for heterogeneous asymmetric catalysis. Our previous work showed that leaching of anions (TfO – ) from the immobilized chiral center (VDPEN-RuOTf) occurred during the recycling process, which led to catalyst deactivation . In this work, the bifunctional polymer is expected to strengthen the recycle stability considering the fact that the presence of acidic sites (TsOH) in the polymer network may compensate the leached anions.…”

“…The (R)-BINAP conjugated microporous polymers reported by Liu and co-workers afforded 70% ee in the asymmetric hydrogenation of quinaldine after coordination with [Ir­(COD)­Cl] 2 . Recently, our group obtained up to 90% ee over the polymer/CNT composite (integrated with VDPEN-RuOTf) in the asymmetric hydrogenation of 2-methylquinoline . However, the catalytic activity is still not high enough in comparison to that of the homogeneous counterpart.…”

“…11 Recently, our group obtained up to 90% ee over the polymer/CNT composite (integrated with VDPEN-RuOTf) in the asymmetric hydrogenation of 2-methylquinoline. 12 However, the catalytic activity is still not high enough in comparison to that of the homogeneous counterpart. Till date, there is still a lack of efficient and highly enantioselective solid catalysts for the asymmetric hydrogenation of quinoline derivatives.…”

Development of efficient solid chiral catalysts with designable linkage for asymmetric transfer hydrogenation of quinoline derivatives

“…Using SBA-ILBF4-TsDPEN50 as a representative sample, the characteristic peaks for C=C vibrations of the phenyl ring at ~1450-1550 cm -1 and the S=O stretching peak at 1157 cm - 13 C NMR spectrum of imidazole-TsDPEN-N-Boc in CDCl3; (d) 13 C CP/TOSS NMR spectrum of SBA-ILBF4-TsDPEN50. [27][28][29], demonstrating the successful incorporation of the chiral ligands with IL linkages into SBA-15 by this one-pot method. In comparison with imidazole-TsDPEN-N-Boc, the characteristic peak of the C=O stretching vibration at 1710 cm -1 shifted slightly to 1700 cm -1 for SBA-ILBr-TsDPENx-N-Boc (Fig.…”