Binding constants (K_DMAP) of 10a, 11, 12, 13, and 10c toward DMAP^a.

Compound	Solvent	K DMAP/M−1b
10a	Toluene	5.2 × 102
11	Toluene	1.5 × 103
12	Toluene	2.0 × 103
13	Toluene	1.8 × 102
10c	Toluene	2.2 × 102
	DMSO	5.3 × 102
	DMSO/H2O (9 : 1, v/v)	4.6 × 102

^aDetermined by titrations with the addition of DMAP monitored using UV-vis absorption spectroscopy.

^bDetermined by the fitting within the error of ±0.1.