Table 1.

Mukaiyama Aldol Reactions of 2-Siloxyindoles and Isatins^a

entry	R1	R3	R2	R4	11	Yield (%)b
1	SEM	H	Me	4-vinyl	11a	77
2	Me	MeO	SEM	H	11b	87
3	Me	MeO	Bn	H	11c	80
4	SEM	H	Bn	H	11d	76
5	Bn	H	SEM	7-F	11e	83
6	SEM	H	Bn	6-phenyl	11f	84
7	SEM	H	Bn	5-(3-pyridyl)	11g	60
8	Me	MeO	Me	4-vinyl	11h	52c

^aConditions: Oxindole (1.0 equiv), isatin (1.0 equiv), BF₃·Et₂O (2.0 equiv), DTBMP (2.5 equiv), –78 °C to –50 °C.

^bYield over two steps of the aldol adduct after purification by silica gel flash column chromatography.

^cThe starting oxindole (15–20%) was recovered.