Table 5.

Synthesis of compounds 9a–f, 9b', 9e', 9f', 10c–f, 10e', 10f', 11a–e and 11b'.

Entry	α-Ketoester	1,2-Diamine	Products	Yield (%)c	Isomers (%)
1	5	8a	9a	83	–
2	5	8b	9b:9b’	68	27:73
3	5	8c	9c	72	–
4	5	8d	9d	87	–
5a	5	8e	9e:9e’	65	44:56
6a	5	8f	9f:9f’	66	55:45
7	6	8c	10c	77	–
8	6	8d	10d	93	–
9	6	8e	10e:10e’	70	42:58
10	6	8f	10f:10f’	66	48:52
11	7	8a	11a	78	–
12	7	8b	11b:11b’	89	50:50
13	7	8c	11c	91	–
14b	7	8d	11d	52	–
15b	7	8e	11e:11e’	56	48:52

^aReaction time of 16 h; ^bReaction time of 24 h. ^cIsolated product.