Cyclopropanecarbaldehyde with two protected hydroxymethyl groups

3,5-Dioxabicyclo[5.1.0]octane-8-carbaldehyde was synthesized in three steps, including initial stereoselective exo-cyclopropanation of 1,3-dioxacyclohept-5-ene with ethyl diazoacetate. The subsequent phosphorylation according to Abramov and Kabachnik-Fields gave the corresponding α-hydroxy(acetoxy)- and α-aminocyclopropylmethylphosphonates with protected hydroxymethyl moieties at the three-membered ring.