A carbocationic route to 3-substituted 1,4-cycloheptadienes
The Lewis acid catalysed reaction of 5-chloro-1, 3-cycloheptadiene 4 with silyl enol ethers yields -cycloheptadienyl substituted carbonyl compounds in high yield. Since 4 is easily prepared from cycloheptatriene, and the cycloheptadienyl cation 3 is preferably attacked at 3-position, this reaction opens an efficient access to 3-substituted 1,4-cycloheptadienes.