Synthesis of Naphthalene‐ and Phenanthrene‐Fused Smaragdyrins and Their BF2 Complexes.

Naphthalene‐ and phenanthrene‐fused [22]smaragdyrin BF2‐complexes were synthesized by 1) Suzuki‐Miyaura coupling of β‐brominated [22]smaragdyrin BF2 complexes with 2‐formylarylboronates, 2) Witting‐type methoxymethylenation of the formyl group, and 3) methanesulfonic acid‐catalyzed cyclization reaction. Subsequently these BF2 complexes were deboronized and oxidized to the corresponding antiaromatic [20]smaragdyrin free bases. The installed fused structures led to decrease of the aromatic characters of the [22]smaragdyrin BF2 complexes and the antiaromatic characters of the [20]smaragdyrin free bases. [ABSTRACT FROM AUTHOR]