Phencyclone cycloheptatriene

The thermal cycloaddition of phencyclone (85) with cycloheptatriene offers additional mechanistic insight into these reactions (Scheme 13). In this case a 57% yield of the corresponding endo [2 -i- 4] adduct was isolated. Further pyrolysis of this material at 170 C provided the decarbonylated pentacyclic material (86) along with an exo [6 h- 4] adduct (87). The course of this reaction can be contrasted with the thermolysis of compound (83). l ile neither of these examples is of great potential synthetic value, they do serve to illustrate some of the typical mechanistic themes which characterize these reactions. 

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