Diastereoselective electrophilic substitution of γ-oxy-substituted benzyllithiums

Reductive lithiation of diastereoisomeric mixtures of 4-aryl-5-methyl-1,3-dioxanes occurs with epimerization at the benzylic centre. Reaction of intermediate organometals with alkyl halides or CO2 afforded 2-methyl-3-substituted-3-phenylpropan-1-ols, or the corresponding lactones, with satisfactory yields and satisfactory to high diastereoselectivities. Observed diastereoselectivities strongly depend on the substitution pattern of starting materials.