Synthesis and transformations of metallacycles

An efficient method for the synthesis of spiro[3.3]heptanes and spiro[3.4]octanes of various structures has been developed using cycloalumination of substituted methylidenecyclobutanes with Et3Al in the presence of Cp2ZrCl2. A possibility of transformation of the in situ formed spiroaluminacyclopentanes to the corresponding thiophanes, selenophanes, and cyclopentanols in high yields and selectivity has been demonstrated.