The mild and efficient one-pot methods to synthesize substituted spirocyclopropanes and spirocyclobutanes are reported. The elaborated procedures based on consecutive cycloalumination of methylenecyclopropanes, methylenecyclobutanes or cycloalkynes assisted by alkyl aluminums and Cp2ZrCl2 as a catalyst provide the formation of target products through Pd catalyzed carbocyclization of the aluminacyclopentane
作者:V. A. D’yakonov、O. A. Trapeznikova、A. G. Ibragimov、U. M. Dzhemilev
DOI:10.1007/s11172-009-0121-4
日期:2009.5
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.