Table 2.

Reaction optimization^a

Entry	cat.	T(°C)	t(h)	conv. (%)b	ee (%)b
1	DHQ-3	rt	0.5	47	5
2	DHQ-3	rt	0.5	16	0
3	Q-5	rt	0.5	38	8
4	Q-6	rt	0.5	< 5	-
5	DHQ-7a	rt	0.5	97	26
6	DHQ-7b	rt	0.5	80	17
7	DHQ-7c	rt	0.5	71	31
8	DHQ-7d	rt	0.5	62	38
9	DHQ-7e	rt	0.5	90	58
c10	DHQ-7f	rt	0.5	95	68
11	DHQ-7g	rt	0.5	98	28
12	DHQ-7f	-20	12	87	78
d13	DHQ-7f	-20	72	80	82
e14	DHQ-7f	-20	24	71	88
f15	DHQ-7f	-20	24	84	88
f16	DHQ-7f	-30	48	81	90

^aUnless specified, the reaction was carried out with 1Da (0.05 mmol) in CH₂Cl₂ (0.05 mL) in the presence of catalyst (0.005 mmol).

^bDetermined by HPLC analysis.

^cAfter 48h, the ee value was reduced to 46%.

^dThe reaction was performed in CH₂Cl₂ (0.50 mL).

^eThe reaction was performed in PhMe (0.50 mL).

^fThe reaction was performed with 1Da (0.05 mmol) and 4 Ǻ MS (5.0 mg) in PhMe (0.50 mL) in the presence of DHQ-7f (0.005 mmol).