Table 3.

Reduction of representative chiral ketones using 1%mol of aminoborate ester 1.^a

Entry	Substrate	Yield (%)b	Ee (%)c	Config.d14
1e		93	95	(R)
2		91	96	(R)
3		90	96	(R)
4		92	99	(R)
5		95	99	(R)
6		88	98	(S)
7		94	99	(R)

^aThe reduction was carried out using 0.7 equivalent of borane-DMS in THF at room temperature.

^bIsolated yield after distillation in a Kugelrohr apparatus.

^cDetermined by GC of acetate on chiral column.

^dAbsolute configuration was determined by comparison of optical rotations with literature values. The configuration of new optical active compounds was assigned by analogy.

^eThe reduction was carried out using 1.7 equivalent of borane-DMS.