Evaluation of various catalyst for the synthesis of 5b in comparison with PCPs(Bi)N(CH2PO3H2)2 under water reflux.
| Entry | Catalyst | (mol% or mg) | Time (h) | Yield (%) | TON | TOF |
|---|---|---|---|---|---|---|
| 1 | [Py-SO3H]Cl57 | 10 | 1.5 | 62 | 620 | 413.3 |
| 2 | NH4NO3 | 10 | 5 | — | — | — |
| 3 | CF3SO3H | 10 | 5 | Trace | — | — |
| 4 | Al(HSO4)3 | 10 | 5 | 37 | 370 | 74 |
| 5 | H3[p(W3O10)4]·XH2O | 10 | 4 | 30 | 300 | 75 |
| 6 | Mg(NO3)2·6H2O | 10 | 4 | — | — | |
| 7 | GTBSA58 | 10 | 2 | 68 | 680 | 340 |
| 8 | p-TSA | 10 | 5 | Trace | — | — |
| 9 | Trichloroisocyanuric acid | 10 | 5 | 32 | 320 | 64 |
| 10 | H3PO3 | 10 | 1.5 | 73 | 730 | 486 |
| 11 | [Fe3O4@SiO2@Pr-DABCO-SO3H]Cl2 (ref. 59) | 10 | 2 | 72 | — | — |
| 12 | APVPB60 | 10 mg | 4 | 58 | — | — |
| 13 | Fe3O4 | 10 mg | 5 | — | — | — |
| 14 | SBISAC61 | 10 mg | 2 | 55 | — | — |
| 15 | SSA62 | 10 mg | 1.5 | 45 | — | — |
| 16 | [PVI-SO3H]Cl63 | 10 mg | 1 | 56 | — | — |
| 17 | PCPs(Bi)BDC-NH2 | 10 mg | 4 | 24 | — | — |
| 18 | PCPs(Bi)N(CH 2 PO 3 H 2 ) 2 | 10 mg | 5 (min) | 95 | — | — |