Dicyclopropa[a,c]naphthalene: a Compound Capable of Existence?

Abstract

The limits for the existence of aromatic compounds are apparently reached in the attempt to generate the title compound 1. If the experiments are carried out in the presence of 1,3‐diphenylisobenzofuran, two bis‐adducts are isolated, which are formally derived from la. However, they are evidently formed by stepwise additions to the double bonds generated successively by reaction of the educt 2 with base. Apparently, the great increase in strain energy in 1 cannot be compensated by the increase in aromatic stabilization. The answer to the question posed in the title is therefore probably not.

Cycloproparenes

“…Thus, Brinker and co-workers synthesized the benzotricyclooctane 130 from odivinylbenzene and subjected it to classical dehydrobromination procedures (Scheme 20). 119 From a very careful study, they were able to show that elimination gives 131 that is trapped by added DPIBF as 133. Isolation of this and resubjection of it to the elimination conditions gives a new ring-fused cyclopropene that is captured by the diene as the syn and anti adducts 134.…”

“…One of the recorded attempts to produce a dicyclopropabenzene has much in common with Müller's synthesis of 129 . Thus, Brinker and co-workers synthesized the benzotricyclooctane 130 from o -divinylbenzene and subjected it to classical dehydrobromination procedures (Scheme ) . From a very careful study, they were able to show that elimination gives 131 that is trapped by added DPIBF as 133 .…”

Combining Aromaticity and Strain with Tetsuo Nozoe—A Passage of Time with Friends

“…By that time in 1989, we and others had attempted the synthesis of the benzenoid nucleus strained by double cyclopropa ring fusions as illustrated by 10–13 . Biscyclopropa–fused aromatics such as 10 had been prepared relatively easily, but the efforts to impose markedly more strain by fusing two three‐membered rings onto one naphthenoid ring failed.…”