Butane-2,3-diacetal (BDA) desymmetrised glycolic acid building block 1 undergoes highly diastereoselective lithium enolate ketone aldol reactions with a range of methyl and mono-substituted methyl ketones to yield, after acid-catalysed deprotection, enantiopure α,β-dihydroxy acid derivatives bearing a quaternary carbon atom at the β-hydroxy centre.
