A cyclopropanol approach to the synthesis of the C13–C21 fragment of epothilones from diethyl (S)-malate

A convenient new approach to the synthesis of the C13–C21 epothilone fragment using the cyclopropanation of the ethoxycarbonyl groups in O-THP protected diethyl (S)-malate with ethylmagnesium bromide in the presence of titanium(IV) isopropoxide followed by site-selective cyclopropane cleavage as the key steps has been performed.