Table 3.

Effect of Nitrogen Protecting Group and Ester Substituent on Selectivity^a

ent	nitrogen PG	ester R	R1	yield, (SM) %a	ee, %b
1	Phthalimide	t-Butyl 5a	Ph 6a	91	88
2	Phthalimide	Methyl 5b	Ph 6b	35 (35)	10
3	Phthalimide	Cyclohexyl 5c	Ph 6c	0	-
4	Phthalimide	Benzyl 5d	Ph 6d	85	20
5	Succinimide	t-Butyl 5e	Ph 6e	61	71
6	Tosyl	t-Butyl 5f	Ph 6f	86	81
7	Tosyl	t-Butyl 5f	4-BrPh 6g	23 (67)	84

^aIsolated yields. Yields in parenthesis are for recovered starting materials.

^bChiral HPLC analysis.