Table 1. Catalyst Optimization for Spiroindolone Formation.

entry	catalyst	solvent	yield (%)[a]	er (config)[b]
1	ScCl3	CH2Cl2	99	--
2	ScCl3•5	CH2Cl2	83	52:47 (R)
3	ScCl2(SbF6)•5	CH2Cl2	99	54:46 (R)
4	SnCl2•6	CH2Cl2	86	51:49 (R)
5	7	CH2Cl2	99	--
6	(S)-8a	CH2Cl2	99	58:42 (R)
7	(R)-8b	CH2Cl2	99	92:8 (S)
8	(R)-8b	CH3Ph	91	80:20 (S)
9	(R)-8b	CH2Cl2/DMF[d]	99	56:44 (S)
10	(R)-8b	DMF	45	65:45 (S)
11	(R)-8b	EtOAc	76	60:40 (S)
12	(R)-8c	CH2Cl2	76	76:24 (S)
13	(R)-8c	CH3CN	86	85:15 (S)
14	(R)-8c	THF	80	80:20 (S)
15	(R)-8c	CHCl3	77	60:40 (S)
16	(S)-8d	CH2Cl2	nd	73:23 (S)
17	(S)-8d	CH3Ph	92	82:18 (S)
18	(S)-8d	CH3Ph[e]	90	83:17 (S)
19	(S)-8d	CH2Cl2/DMF[c]	90	80:20 (S)
20	(S)-8d	DMF	70[d]	82:18 (S)
21	(S)-8e	CH2Cl2	99	68:32 (S)
22	9a	CH2Cl2	99	75:25 (R)
23	9a	CH3Ph	60	76:24 (R)
24	9b	CH2Cl2	NR	--
25	(R)-8b/MgF2	CH3Ph	85	77:23 (S)

Reactions performed with 1.2 equiv of isatin under argon. Reactions run from 48-96h.

^[a]Isolated yield.

^[b]Enantioselectivity determined by HPLC analysis using chiral stationary phase.

^[c]4:1 DCM/DMF.

^[d]40°C.

^[e]Reaction performed at -15°C.