ChemInform Abstract: Light-Induced, Thermal, and Acid-Catalyzed π-Skeletal Rearrangements of Five-Ring-Annelated Heptalenes.
Abstract
The interconversions of (I)/(II) and (III)/(IV) by irradiation and thermolysis (exemplified in the scheme by the transformations of (IIIb)/(IVb), the former compound being obtained from (VI)), as well as the acid-catalyzed rearrangement of (IIb) to give (Ib) (in HCl/CD3OD; tab.
ChemInform Abstract
The interconversions of (I)/(II) and (III)/(IV) by irradiation and thermolysis (exemplified in the scheme by the transformations of (IIIb)/(IVb), the former compound being obtained from (VI)), as well as the acid-catalyzed rearrangement of (IIb) to give (Ib) (in HCl/CD3OD; tab. with isotopic compositions of major and minor products) are described in detail. The positions of the individual equilibria are discussed in terms of steric hindrance exerted by the respective substituents. The absence of a diastereomeric by-product in the conversions of (VII) and (VIII) indicate that the double bond shifts proceed with retention of configuration of the heptalene skeleton.
