Table 1.

Enantioselective Diels–Alder reactions catalysed by metallo–ATP complexes^a.

Entry	Azachalcone	Metal cofactor	Conversion (%)	Endo/exo	ee (%, exo)	ee (%, endo)
1	1a	None	3	85:15	29	16
2	1a	MgCl2	3	84:16	22	5
3b	1a	Cu(NO3)2	70	92:8	0	0
4	1a	Cu(NO3)2	90	91:9	74	65
5	1a	Zn(NO3)2	3	84:16	28	13
6	1a	Co(NO3)2	11	85:15	31	13
7	1a	Ni(NO3)2	23	87:13	44	35
8	1a	Cu(bpy)(NO3)2	9	89:11	42	33
9	1a	Cu(dmbpy)(NO3)2	5	87:13	34	29
10	1a	Cu(phen)(NO3)2	8	90:10	48	46
11	1a	Cu(OTf)2	98	91:9	79	72
12c	1a	Cu(OTf)2/MgCl2	90	91:9	66	53
13d	1a	Cu(OTf)2	71	89:11	48	44
14	1b	Cu(OTf)2	90	92:8	88	80
15	1c	Cu(OTf)2	85	92:8	80	77
16	1d	Cu(OTf)2	72	96:4	62	50
17	1e	Cu(OTf)2	80	91:9	93	39
18	1f	Cu(OTf)2	85	84:16	76	84
19	1g	Cu(OTf)2	91	91:9	56	44
20	1h	Cu(OTf)2	80	92:8	80	67

bpy 2,2′-bipyridine, dmbpy 4,4′ -dimethyl-2,2′-bipyridine, phen 1,10-phenathroline.

^aReaction conditions: 1 (1 mM), 2 (200 mM), ATP (250 μM), metal cofactor (50 μM), MES buffer (20 mM, pH 5.5), 4 °C, 24 h for 1a and 72 h for 1b–h. The conversion of 1a was calculated by HPLC and the conversions of 1b–h were determined from the crude products by ¹H NMR. The diastereoselectivity (endo/exo) and enantioselectivity were determined from the crude products by chiral HPLC. All data were the averages of at least two individual experiments (reproducibility: ±5% conversion, ±3% endo/exo and ±3% ee).

^bWithout ATP.

^c10 mM MgCl₂ was added.

^dReaction at 37 °C.