Differentiation between the ethoxycarbonyl groups in diethyl malate via their titanium-catalyzed reductive cyclopropanation with ethylmagnesium bromide and subsequent site-selective three-carbon ring cleavage

Ethoxycarbonyl groups in O-THP protected racemic diethyl malate 1 were differentiated by their reductive cyclopropanation with ethylmagnesium bromide in the presence of titanium(IV) isopropoxide and subsequent site-selective C1–C2, C2–C3 or both C1–C2 and C1–C3 ring cleavage of the cyclopropyl groups of the resulting bis-cyclopropanol 2.