Diastereoselective formation of β-hydroxyketones by the reduction of Ketene dimers

A general method for the diastereoselective formation of β-hydroxyketones by the reduction of ketene dimers was developed. Methylphenylketene dimer was reduced with optimal diastereoselectivity (dr up to 6:1) using LiBH4. However, more generally LiAlH4 was found to be the most effective reducing system with respect to diastereoselectivity (dr up to >99:1) and yield (62->99% for 10 examples).