Table 4.

Evaluation of ligand structure in additions of MeLi to imine 11

entry	R3	R4	ligand	temp, °C	yield, %a	erb
1	Et	CHMe2	12bb	−63	86	86.5:13.5
2	Et	CMe3	12bc	−63	96	95.5:4.5
3	Et	CMe3	12bc	−78	83	94.5:5.5
4	Et	CMePh2	12be	−63	21	82.0:18.0
5	Et	CMePh2	12be	−41	90	84.5:15.5
6	Me	CMe3	12ac	−75c	81	96.5:3.5
7	CH2CHMe2	CMe3	12cc	−75c	97	93.5:6.5
8	CH2(Me)c-Pr	CMe3	12jc	−75c	92	88.5:11.5
9	CHMe2	CMe3	12ec	−75c	77	93.5:6.5

^aYield of chromatographically homogeneous material.

^bAll compounds have R configuration. Determined by CSP-HPLC analysis.

^cInternal temperature.