Dzhemilev reaction for the synthesis of spiro[3.3]heptane and spiro[3.4]octanes

For the first time cycloalumination of methylenecyclobutane with the aid of Et3Al in the presence of Cp2ZrCl2 leading to 6-ethyl-6-aluminaspiro[3.4]octane has been realized. The latter, without isolation, was converted into spiro[3.3]heptane, 6-thiaspiro[3.4]octane and also spiro[3.4]octan-6-ol and 6-spiro[3.4]octyl formate with high yields and selectivity.