Zirconium-Mediated Synthesis of Cyclobutyl Derivatives

Significance

The authors described the stereoselective preparation of metalated cyclobutane derivatives through treatment of Z-vinyl carba­mate with Et₂ZrCp₂. The resulting cyclobutyl zirconium reagents reacted with various electrophiles leading only to syn-diastereomers. It is believed that the reaction proceeds through a carbometalative ring expansion followed by an intramolecular migratory insertion.