Cationic Cyclization Involving a Remote Allene Function in the Trifluoroethanolysis of Hepta-5,6-dienyl Toluene-p-sulphonate

The remote allene function participates efficiently in the trifluoroethanolysis of hepta-5,6-dienyl toluene-p-sulphonate, leading to the cyclized 2-methylenecyclohexyl cation

Cationic Cyclization Involving a Remote Allene Function in the Trifluoroethanolysis of 5,6-heptadien-1-yl p-toluenesulfonate

In order to determine whether a remote allene function would undergo intramolecular nucleophriftsubstitution, 5,6-heptadien-1-yl p-toluenesulfonate (14) was synthesized and solvolyzed. The major products of the trifluoroethanolysis of 14 were the cyclic trifluoroethyl ethers of 2-methylenecyclohexanol (24) and 1-cyclohexenemethanol (25). The minor product was the direct displacement product, 5,6-heptadien-1-yl 2,2,2-trifluoroethyl ether (23). The cyclic triflurorethyl ethers were also obtained from the solvolysis of two arenesulfonate esters of 24 and 25, the alcohols having been synthesized by an independent route. Kinetic data showed a rate enhancement for 14 relative to its saturated analog