Association constants for XB donor and Michael reaction substrate pairs.
| Entry | XB acceptor | XB donor | K obs a (M−1) |
|---|---|---|---|
| 1 |
|
|
9.4 |
| 2 | 1b |
|
2.5 |
| 3 | 1b |
|
0.5 |
| 4 | 1b |
|
0.4 |
| 5 | 1b |
|
12.6 |
| 6b | 1b | B | 3.4 |
| 7 | 6 | 9 | 1.3 |
| 8 | 8 | 9 | 14.0 |
a
The Kobs was measured in toluene-d8 and determined by fitting the 1H NMR titration data of the N- or O-methyl protons to the 1 : 1 binding isotherm of BindFit.28 The given Kobs is the calculated approximate mean value of two parallel experiments; in all cases the estimated standard errors fall below 10%. Full details are given in the ESI.
b
Determined by fitting the 19F NMR titration data of the fluorine atom ortho to the iodine atom to the 1 : 1 binding isotherm of BindFit.