Table 1.

Optimization of enantioselective additions to sulfonylmethyl indoles.

entry	catalyst	base	t(°C)	M	ee (%)b
1c	4c	KF/Alumina	rt	0.2	20
2	4c	KF/Alumina	rt	0.2	60
3	4c	KF/Alumina	−20	0.2	57
4	4c	KF/Alumina	−78	0.2	49
5	4c	KF	rt	0.1	68
6	4c	Na2CO3	rt	0.1	61
7	4c	K2CO3	rt	0.2	70
8	4a	K2CO3	rt	0.2	56
9d	4b	K2CO3	rt	0.2	73
10	4c	K2CO3	rt	0.1	78
11d	4c	K2CO3	rt	0.1	81

^aAll reactions were performed using 2 equivalents of phenylnitromethane on a 0.1 mmol scale and resulted in less than 1.5:1 dr material and between 30–80% yield.

^bEnantiomeric ratios were measured using chiral stationary phase HPLC and are reported for the major diastereomer.

^cDichloromethane was used instead of toluene.

^d1 equivalent of phenylnitromethane was used.

^eAbsolute stereochemistry assigned by correlation. See Supporting Information for details.