Synthesis, Structure, and Photophysical Properties of Highly Substituted 8,8a‐Dihydrocyclopenta[a]indenes

Abstract

Blaulicht: Eine Palladium‐katalysierte Cyclotrimerisierung von 1,2‐Diarylacetylenen wurde entwickelt und in der Synthese von hoch substituierten 8,8a‐Dihydrocyclopenta[a]indenen eingesetzt. Ein solches Cycloaddukt, 1, zeigt eine ungewöhnliche aggregationsinduzierte Emission mit intensiver blauer Fluoreszenz (siehe Bild). Die Strukturen der Produkte wurden durch Kristallstrukturanalysen bestätigt.

Palladium‐Catalyzed Ring‐Expansion Reaction of Indoles with Alkynes: From Indoles to Tetrahydroquinoline Derivatives Under Mild Reaction Conditions

“…In the initial step, regioselective direct electrophilic aromatic palladation at the 3-position of the indole forms an indol-3-ylpalladium species A. [12] The sub-sequent insertion of two alkyne molecules forms a dienylpalladium intermediate C. [13] Then, the intramolecular 5-exo-dig insertion [14] G (route B). Then a successive second intermolecular electrophilic aromatic palladation of another indole molecule would generate intermediate H, which undergoes reductive elimination to give the product 3 aa.…”

Palladium‐Catalyzed Cycloisomerizations of Diarylacetylenes: Synthesis, Structures, and Physical Properties of Highly Substituted Naphthalenes and 8,8 a‐Dihydrocyclopenta[a]indenes

“…[9,29] The solution containing 3 a in dichloromethane or THF is practically nonfluorescent, but it becomes highly luminescent in crystal (or solid) form. To understand this abnormal AIE, the quantum yield (F F ) of compounds 3, 6, and 7 a-nBu (ca.…”

“…[9] Here, the full scope and limitations of the new cyclotrimerization process were studied. The photophysical and electrochemical properties of the cycloadducts and their analogues were also analyzed and compared with computational predictions based on density functional theory.…”

Metal‐Catalyzed Cascade Reactions: Useful Synthetic Tools for the Preparation of Polycyclic Arenes

“…Metal‐catalyzed [2+2+2] cyclotrimerization of alkynes is an effective synthetic method for preparing PAs . Unlike the conventional cycloaddition, an unusual palladium‐catalyzed cycloisomerization of diarylalkynes furnished highly substituted 8,8a‐dihydrocyclopenta[ a ]indenes 55 , accompanied by small amounts of hexaarylbenzenes 56 or naphthalenes 57 (Scheme ) . This protocol requires water and organophosphines.…”

“…The role of the added water was verified by isotope‐labeled experiments for the formation of the parent compound 55 (Ar = Ph; R 1 , R 2 , R 3 = H). Most hydrogen atoms at position C8 come from external water, but some (around 25%) are provided by the phenyl ring in diphenylacetylene [71a] …”