Phenylkationen als reaktive Zwischenstufen bei der Solvolyse von Dien-in-yl-triflaten

Die Synthese, Trennung und Solvolyse der steroisomeren 1,4-Dimethyl-1,3-hexadien-5-in-1-yl-triflate 15a–c in verschiedenen Losungsmitteln wird beschrieben. Dabei reagieren die (E)-Isomeren 15a–c im Gegensatz zu den (Z)-Isomeren 15a–c bevorzugt uber ein intermediares Phenylkation 16 zu den Phenylethern 17. Uber weitere mechanistische Untersuchungen, die fur die Bildung der intermediaren Phenylkationen 16 sprechen, wird berichtet. Die Entstehungsweise der Benzylderivate 18 wird diskutiert. Phenyl Cations as Reactive Intermediates in the Solvolysis of Dien-in-yl Triflates The synthesis, separation, and solvolysis of the stereoisomeric 1,4-dimethyl-1,3-hexadien-5-yn-1-yl triflates 15a–c in various solvents are described. In contrast to the (Z)-isomers 15a–c, the (E)-isomers 15a–c react preferably via an intermediate phenyl cation 16 to give the phenyl ethers 17. Further mechanistic investigations which support the formation of the intermediate phenyl cations 16 are described. The formation of the benzylic derivatives 18 is discussed.

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