Synthesis of Indeno[b]indole and Naphtho[a]carbazole Derivatives Involving Diels‐Alder Reaction of Isobenzofurans

Abstract

Diels‐Alder reaction of 1,3‐diarylisobenzofurans with cyclopenten‐1‐one as well as 2‐cyclohexen‐1‐one in the presence of TMSOTf in DCM at 0 °C furnished 4,5‐diarylbenzo[e]inden‐1‐ones and 6,7‐diarylbenzo[f]α‐tetralones. The benzo[e]inden‐1‐ones/benzo[f]α‐tetralones upon Fischer indolization led to the formation of indeno[b]indoles and dihydronaphtho[a]carbazoles, respectively.

Diels–Alder Reaction of Isobenzofurans/Cyclopentadienones with Tetrathiafulvalene: Preparation of Naphthalene, Fluoranthene, and Fluorenone Derivatives

“…It is obvious that the oxidation potential of TTF can be easily tuned by an annulation of the aromatic ring system to its framework. Hence, in a further continuation of our studies on synthetic utility of IBF (isobenzofurans) derivatives, we report herein our preliminary findings on Diels–Alder reaction of TTF with 1,3-diarylisobenzofuran as well as cyclopentadienone derivatives.…”