A general method for the diastereoselective formation of beta-hydroxyketones by the reduction of ketene dimers was developed. The reduction of ketene homodimers, derived from alkylarylketenes and dim-ethylketene, and ketene heterodimers, derived from methylketene and ethylphenylketene or diphenylketene, was investigated. Methylphenylketene dimer was reduced with optimal diastereoselectivity (dr = 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). (C) 2012 Elsevier Ltd. All rights reserved.