Annulated oxa-cage frameworks via Claisen rearrangement and ring-closing metathesis

In our quest to design high-density fuels, we report a variety of structurally interesting new annulated oxa-cage frameworks. Here, we investigated a linear synthetic sequence, which relies on reductive C-C bond cleavage and ring-closing metathesis as key steps. For this purpose, we utilized inexpensive and readily available starting materials such as hydroquinone and endo-dicyclopentadiene. Transannular cyclization during Grignard addition played a significant role in the design of intricate caged compounds. The creation of these new oxa-cage systems is a challenging task by traditional methods. The structure of the target compound has been unambiguously established by single-crystal X-ray diffraction studies. These data indicate that density of the RCM compound is larger than the cubane density. (C) 2020 Published by Elsevier Ltd.