Table 2.

Binding constant K_HG (10³ M⁻¹) of boronic acid hosts, K_HG(S,S) with (S,S)-hydrobenzoin and K_HG(R,R) with (R,R)-hydrobenzoin

Guest	Host-1	Host (S,S)-2	Host (R,R,R,S)-4	Host (R)-6	Host (S)-6	Host (R)-8	Host (S)-8
KHG(S,S)	1.42 ± 0.04	13.6 ± 0.13	3.55 ± 0.04	3.78 ± 0.06	6.38 ± 0.05	5.85 ± 0.06	4.17 ± 0.04
KHG(R,R)	1.26 ± 0.03	4.77 ± 0.02	5.22 ± 0.07	5.93 ± 0.07	3.94 ± 0.04	3.96 ± 0.05	5.55 ± 0.06

All titrations were carried out in 100% MeOH, 10 mM para-toluenesulfonic acid, and Hunig's base buffer (pH 7.4). All measurements were taken at 25 °C. The error reported here results from the computer fit to the experimental isotherm. In our previous experience, there is ≈10% error, at most, in the reproducibility in the K_HG value.