Preparation of highly hindered polyenes with tert-butyl groups in internal positions.

The conjugated tetraenes 3 and 4 a-c have been prepared and shown to possess an orthogonal structure. This was not only demonstrated by their spectroscopic properties and X-ray structural analysis of solid representatives (e.g., 4 a-c) but also by the resolution of these chiral compounds by GC and HPLC chromatography using various chiral selector systems. The chemical behavior of the typical tetraene 4 a has been studied using bromination, hydrogenation, epoxidation, and photo equilibration reactions.