Table 1.

Cycloaddition reaction of CO₂ with 1‐ethyl‐2‐phenylaziridine under various conditions^a)

Entry	Catalyst 1 [mg]	T [°C]	Yieldb) [%]	Regio‐selc)
1	80	25	30	97:3
2	80	80	91	97:3
3	80	100	>99	98:2
4	80	120	85	97:3
5d)	80	100	92	98:2
6	40	100	89	98:2
7e)	0	100	45	92:8
8f)	0	100	43	92:8
9g)	0	100	47	>99
10	0	100	79	98:2
11h)	40	100	95	96:4

^a)Reaction conditions: 1‐ethyl‐2‐phenylaziridine (294.4 mg, 2.0 mmol), solvent‐free, catalyst 1, TBAB (32.4 mg, 0.1 mmol), CO₂ (2.0 MPa), 12 h, 80 mg catalyst 1 loading (based on metal center, about 10 mol%);

^b)Total yield of 2a and 3a determined by ¹H NMR using 1,3,5‐trimethoxybenzene as an internal standard;

^c)Molar ratio of 2a to 3a;

^d)CO₂ (1.0 MPa);

^e)TBAB (32.4 mg, 0.1 mmol) and Cu(OAc)₂ (39.9 mg, 0.2 mmol);

^f)TBAB (32.4 mg, 0.1 mmol) and Cu(NO₃)₂ (37.4 mg, 0.2 mmol);

^g)TBAB (32.4 mg, 0.1 mmol) and CuSO₄ (31.9 mg, 0.2 mmol);

^h)HKUST replaces compound 1 to conduct this reaction, catalyst loading (based on metal center, about 10 mol%).