Table 3.
pH-independent second-order rate constants for amine-catalyzed retroaldol reactions of 4-hydroxy-4-(6-methoxy-2-naphthyl)-2-butanone
| Amine | pKa | kmax (M-1 s-1) * |
| Cyanomethylamine | 5.3 | 5.8 × 10-6 |
| Trifluoroethylamine | 5.7 | 7.1 × 10-6 |
| Propargylamine | 8.2 | 1.0 × 10-4 |
| Bromoethylamine | 8.5 | 1.5 × 10-4 |
| Chloroethylamine | 8.8 | 4.0 × 10-4 |
| Ethanolamine | 9.5 | 6.9 × 10-4 |
| Butylamine | 10.6 | 5.3 × 10-3 |
| Methylamine | 10.6 | 2.6 × 10-3 |
*kmax refers to the rate constant for the fully deprotonated, neutral species, whereas kobs is used elsewhere for the observed rate constant for an amine at a given pH.