Table 2.

Cyclizations with silyloxyindole substrates.^a

entry	substrate	acid chloride	major product	drb	yield(%)c
1	8		25	4.1:1 (2.1:1)	68 (46)
2	8		26	12:1 (1.7:1)	67 (42)
3	8		27	7.2:1 (3.7:1)	38 (30)
4	8		12	4.5:1 (2.4:1)	66 (47)
5d	8		28	18:1 (1.8:1)	58 (37)

^aRepresentative procedure: Cp₂Zr(H)Cl (1.25 equiv) was added to a 0.1 M solution of the indole nitrile in CH₂Cl₂ under Ar. After stirring at rt for 15 min the acid chloride and Sc(OTf)₃ were added. The mixture stirred overnight at rt.

^bThe ratio refers to the quaternary center. The value in parentheses refers to the ratio of the major stereoisomer to all other stereoisomers.

^cCombined yield of all stereoisomers. The yield of the major stereoisomer is in parentheses.

^dZnCl₂ was used instead of Sc(OTf)₃.