Oxepins theoretical studies

Experimental and theoretical studies on gold- and platinum-catalyzed reactions " explained the mechanism of this phenol synthesis. Oxepines and arene oxides have been observed in the reaction catalyzed by Au(III). ... 

Structural information in the crystalline state can be obtained directly by x-ray diffraction studies, but this method has not been used extensively in the arene oxide-oxepin series since the majority of the monocyclic arene oxide-oxepins synthesized to date have been liquids and since chemical instability at ambient temperature is a common feature of many mono- and polycyclic arene oxides. X-ray crystal structure analysis has been carried out on the relatively stable K-region arene oxides 2-4. ° Similarly, an x-ray analysis of 5, a crystalline annelated benzene oxide (which, however, exists in both arene oxide and oxepin form in solution), has been reported and indicates that the six-membered ring is almost planar. The oxepin ring in compound 6 has been shown to exist in the boat conformation both in solution and in the crystalline state. The structural information thus obtained in the crystalline state is totally consistent with the spectroscopic data and the chemical reactivity of the arene oxides in solution and has been used in theoretical studies of the arene oxide-oxepin system. ... 

Meanwhile, reactions of toluene 1,2-epoxide (C) and 2-methy oxepin (D) have not been studied well. According to quantum chemical calculations, the reaction rate constants of the former epoxide with OH largely at silxl0 ° cm molecule s (Cartas-Rosado and Castro 2007) reproducing well the experimental value of 2 X 10 ° cm molecule s (Klotz et al. 2000), the theoretical value of the rate constant of OH with the oxepin is very small as 1 x 10 " cm molecule s . The formation of the reaction product 6-oxohepta-2,4-dienal obtained experimentally by Klotz et al. (2000) is also predicted by theoretical calculation, and the reaction pathways is proposed by Cartas-Rosado and Castro (2007), as shown in Reaction Scheme 7.12. 

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