Table 1. Relative energies of the eight diastereomeric transition states for the benzoin condensation of benzaldehyde with catalyst I.

	Transition-state geometry*
Catalyst	Enolamine	Enolamine face	Aldehyde face	Product configuration	ΔGrel, kcal/mol†
S	E	si	re [TS1]‡	S	0 (0)
S	E	si	si [TS2]‡	R	2.8 (15.0)
S	Z	re	re	S	2.9 (23.4)
S	E	re	re	S	7.3 (21.6)
S	Z	si	re	S	7.8 (4.5)
S	E	re	si	R	8.4 (12.0)
S	Z	re	si	R	9.8 (30.0)
S	Z	si	si	R	17.8 (23.4)

^*See Data Set 1, which is published as supporting information on the PNAS web site, for figures of structures and Cartesian coordinates.

^†Relative energies obtained by single-point B3LYP/6-31G(d) calculations. Energies in parentheses are relative energies calculated by using IMOMO (B3LYP/6-31G(d)//AM1).

^‡Depicted in Fig. 5.