Cycloaddition Reaction of Ethyl Thioxoacetate and the Dienamine Derived from Pummerer's Ketone

Table 2

Nuclear overhauser difference NOE (CDCl ₃; 200 MHz) of the cycloadduct (21).

Irradiated protons	δ	1-H	2B-H	2A-H	4-H	4a-H	6-H	7-H	8-Me	9-H	9b-Me	11-H	OCH2CH3	OCH2 CH3
1-H	2.92	−74.75	2.06	1.62	0.09	0.17	0.14	0.53	0.03	4.54	1.47	4.78	0.64	0.45
2B-H	2.57	2.72	−56.59	21.16	0.26	0.26	0.32	0.23	0.31	0.67	−0.3	−0.03	0.24	0.13
2A-H	1.97	1.99	20.95	−62.44	0.26	−0.01	0.16	0.09	−0.71	−0.13	−0.15	0.29	0.51	0.29
4-H	3.35	−0.03	0.08	0.26	−65.22	6.1	0.08	0.07	0.07	0.08	−0.12	−0.06	0.17	0.12
4a-H	4.86	0.08	0.12	0.22	7.98	−83.16	0.2	0.12	0.36	0.06	2.71	0.06	0.56	0.09
8-Me	2.26	0.01	0.09	−0.52	0.09	0.38	0.21	7.02	−262.8	6.98	0.1	0.06	0.16	0.32
9b-Me	1.63	4.37	0.34	0.59	−0.43	11.28	0.57	0.31	0.8	4.68	−224.96	18.83	0.96	0.40
11-H	4.11	5.62	−0.24	0.30	0.36	0.91	0.07	−0.27	0.19	0.14	6.73	−76.67	−7.37	0.52
OCH2CH3	4.21	0.40	0.17	0.35	0.13	0.26	0.09	0.22	0.30	0.05	0.57	−6.58	−150.13	4.98
OCH2CH3	1.28	0.13	0.07	0.27	0.09	0.12	0.12	0.30	0.26	0.13	0.04	0.28	4.56	−232.28