Synthesis and Dimerization of 2,3-Dimethyl-5-silaspiro(4.4)nona-2,7-diene.Structure Determination of 2,3,12,13-Tetramethyl-5,10-

摘要

Unsymmetrical 2,3-dimethyl-5-silaspiro(4.4)nona-2,7-diene (I) has be en preparedby a dissolving-metal reaction between 1,1-dichloro-1-silacyclopent-3-ene (III) and 2,3-dimethyl-1,3-butadiene. Ring-opening reactions of I catalyzed by alkyllithium reagents and hexamethylphosphoramide (HMPA) have been explored. High yields of the dimer 2,3,12,13-tetramethyl-5,10-disiladispiro4.4.4.4octadeca-