CO₂ cycloaddition reaction to epoxides using complexes 1 and 2^a.

Entry	Epoxide	Catalyst	1 or 2 (mol%)	TBAB (mol%)	Time (h)	% Convb	Ref.
1	ECH	1-TBAB	1	2	4	100	Twc
2	EBH	1-TBAB	1	2	4	100	Twc
3	SO	1	1	—	4	0	Twc
4	ECH	2-TBAB	1	2	4	100	Twc
5	SO	1-TBAB	1	2	4	95	Twc
6	SO	2-TBAB	1	2	4	93	Twc
7	SO	TBAB	—	2	4	26	Twc
8	AGE	1-TBAB	1	2	4	85	Twc
9	AGE	2-TBAB	1	2	4	92	Twc
10	BGE	1-TBAB	1	2	4	85	Twc
11	BGE	2-TBAB	1	2	4	82	Twc
12	SO	1-TBAB	1	2	6	100	Twd
13	SO	TBAB	—	2	6	33	Twd

^aReaction conditions: ECH = 0.5 mL (6.38 mmol); SO = 0.5 mL (4.38 mmol); AGE = 0.5 mL (4.27 mmol); BGE = 0.5 mL (3.50 mmol); EBH = 0.5 mL (5.88 mmol).

^bPercentage conversions of the catalytic reactions were evaluated with the help of ¹H NMR spectroscopy according to the conversion formula shown in Fig. S26.

^c5 bar CO₂ pressure.

^d1 bar CO₂ pressure.