Table 1.

Ratios of syn/anti Isomers at Different Temperatures for Model Compounds 6a-14a. The experiments were performed in CDCl₃ unless stated otherwise.

Entry	Compound	Ar1	Ar2	syn/anti Ratio in CDCl3 at different temp.
				−10	−20	−30	−40	−50 (°C)
1	6a	C6H4NMe2	C6F5	15.7	17.5	20.7	26.5	28.0
2	6b	C6H4NMe2	C6HF4	5.37	6.04	6.61	7.36	8.87
3	6c	C6H4NMe2	C6H2F3	1.62	1.70	1.83	1.90	1.93
4	6d	C6H4NMe2	C6H3F2	0.72	0.71	0.72	0.72	0.74
5	6e	C6H4NMe2	C6H4F	0.54	0.53	0.48	0.47	0.47
6	7a	C6H5	C6F5	11.0	11.7	13.7	15.7	18.0
7	7f	C6H5	C6H4NO2	2.63	2.78	2.94	3.08	3.27
8	7e	C6H5	C6H4F	0.55	0.54	0.53	0.50	0.47
9	7g	C6H5	C6H5	0.30	0.29	0.26	0.24	0.21
10	7h	C6H5	C6H4Me	0.19	0.17	0.16	0.14	0.12
11	7i	C6H5	C6H4OMe	0.23	0.22	0.19	0.18	0.17
12	8a	C6H4NO2	C6F5	5.6	6.0	6.8	7.6	8.9
13	8f	C6H4NO2	C6H4NO2	2.66	2.73	2.85	2.94	3.05
14	8e	C6H4NO2	C6H4F	0.96	0.92	0.90	0.89	0.89
15	8g	C6H4NO2	C6H5	0.59	0.56	0.55	0.53	0.50
16	8h	C6H4NO2	C6H4Me	0.54	0.51	0.48	0.46	0.44
17	8i	C6H4NO2	C6H4OMe	0.61	0.59	0.57	0.54	0.52
18	9a	C6H4Me	C6F5	13.5	15.2	17.2	18.7	21.3
19	10a	C6H4OMe	“	10.6	12.0	13.1	15.8	18.2
20	11a	C6H3Me2	“	15.2	17.5	19.8	21.0	23.3
21	12a	C6H2Me3	“	17.1	19.1	21.3	23.8	26.1
22	13	C6H4Me	CH3	1.99	2.08	2.27	2.40	2.58
23	14	CH3	CH3	0.32	0.32	0.30	0.28	0.27