New lithium enolates of alpha-hydroxy ketones, derived from camphor, are ev
aluated for asymmetric aldol reactions in the presence of lithium chloride.
The diastereoselectivity of the reactions between the lithium enolate of 3
and a variety of achiral aldehydes is strongly influenced by the lithium c
hloride salt. In these instances, the achieved levels of asymmetric inducti
on, typically 95:5 dr, are in the range of those attained in aldol reaction
s involving the lithium enolate of the methyl ketone 4, which is sterically
more demanding. The resulting aldol adducts are easily transformed into be
ta-hydroxy carboxylic acids, ketones, and aldehydes with concomitant recove
ry of the camphor, the chiral controller of the process, which can be reuse
d.