Cyclodienyl 1,3-dianionic synthons: A novel synthesis of 5,5-dimethyl-1,3-bis-(trimethylsilyl)cyclohexa-1,3-diene and its Diels-Alder Ï4s+Ï2s cycloadditions with six dienophiles

摘要

The synthesis of 5,5-dimethyl-1,3-bis(trimethylsilyl)cyclohexa-1,3-diene: a novel cyclic 1,3-dianionic synthon is reported by the Wurtz-Fittig coupling reaction of 1,3-dichloro-5,5-dimethylcyclohexa-1,3-diene with metallic sodium and chlorotrimethylsilane in anhydrous ether solvent. The compound on further Diels-Alder Ï4s+Ï2s cycloaddition with five N-substituted maleimides gave five novel cycloadducts: the N-substituted 11,11-dimethyl-1,8-bis(trimethylsilyl)-4-azatricyclo5.2.2.0 2,6undec-8-ene-3,5-diones; and reaction with maleic anhydride yielded the novel 11,11-dimethyl-1,8-bis(trimethylsilyl)-4-oxotricyclo5.2.2.0 2,6undec-8-ene-3,5-dione in 94-97% overall yields. © 2012 Bentham Science Publishers.