Formation of cycloheptatrienes by alkyllithium induced cyclisation of polyunsaturated enol ethers

Two polyunsaturated enol ethers have been shown to react with t-butyllithium in THF with formation of cycloheptatriene derivatives as the major volatile products. This novel reaction is explained as a 7-endo-trig cyclisation of the allylic lithium derivative formed by deprotonation at C-5.