Table 2.

Michael addition of diphenyl phosphite (2) to trans-β-nitrostyrene (1a) catalyzed by 5^[a].

entry	solvent	temp [°C]	time	conv [%][b]	ee [%]
1	toluene	rt	1 h	90	94
2	Et2O	rt	1 h	81	93
3	tBuOMe	rt	1 h	71	94
4	THF	rt	1 h	99	93
5	MeCN	rt	1 h	89	90
6	acetone	rt	1 h	64	93
7	CH2Cl2	rt	15 min	99	96
8	CH2Cl2	0	30 min	99 (95[c])	97
9	CH2Cl2	−10	1 h	99	98
10	CH2Cl2	−20	2 h	99	98.4

^[a] Reactions were carried out on 0.20 mmol of 1a with 1.25 equiv of 2 and 10 mol% 5 in 1.0 mL solvent.

^[b] Reaction conversions were determined by ¹H-NMR.

^[c] Isolated yield.