Table 1.

Isomerization of Selected Spirooxindole-Containing Compounds^a

Entry	Compounds (a–d)	R1	R2	R	Yieldb(%)	Ratio after Oxidation a:b: (c+d)c	Ratio after Aging a:b: (c+d)c,d
1	1	H	H	NMe2	50e	95:2:3	6:71:24
2	2	H	H	NHMe	61	87:5:8	3:71:26
3	3	H	F	NMe2	57	75:19:6	35:46:19
4	4	H	F	NHMe	84	67:2:31	9:79:12
5	5	H	F		86	88:2:10	1:80:19
6	6	H	F		79	89:10:1	12:61:27
7	7	H	F	OEt	74	89:6:3	44:50:6
8	8f	H	F	OH	25g	—	41:34:25h
9a	9	H	F	NH2	56	0:44:56	0:96:4
10	10	F	H	NMe2	60	56:25:19	10:71:19i 2:88:8
11a	11	F	H	NHMe	87	19:52:27	1:74:25
12	12	F	H		81	30:32:38	3:58:37
13a	13	F	H		50	15:67:18	2:74:24

^aIn cases of 9, 11, 12 and 13, the cis-cis isomers were obtained as the predominant products of ceric ammonium nitrate oxidation without aging (equilibrium in CH₃CN and H₂O at pH 8 for 3 days)

^bIsolated yield after flash column chromatography

^cRatio determined by HPLC analysis; assignments were not made for c and d;

^dThe combined yield of a to d in the aging step was determined from the yield in the oxidation step;

^eYield after HPLC separation;

^fCompound 8a-8d was obtained from the hydrolysis by LiOH-THF-H₂O of 7a;

^gHydrolysis yield;

^hStarting from pure 8a;

ⁱRatio after crude product was allowed to stand in MeOH for 2 h.