Synthesis of Acridines by the [4 + 2] Annulation of Arynes and 2-Aminoaryl Ketones

Abstract

The reaction of 2-aminoaryl ketones and arynes generated by the treatment of various o-(trimethylsilyl)aryl triflates with CsF results in [4 + 2] annulation to afford substituted acridines in good yields.

Synthesis of Pyrido[1,2-a]indole Malonates and Amines through Aryne Annulation

“…9 As a result, aryne intermediates have provided chemists with the ability to rapidly access a plethora of interesting heterocycles and carbocycles, including indoles, 10 xanthones, 11 acridines, 12 indazoles, 13 and benzotriazoles, 14 among others, using mild and functional group tolerant reaction conditions. The ability to expediously synthesize biologically important compounds continues to motivate our labs to explore the full potential of aryne-based methodologies.…”

Transition-Metal-Free Synthesis of Benzo-Fused Five- and Six-Membered Heterocycles Employing Arynes

“…The inserted product undergoes a subsequent S N Ar reaction, affording the acridones. Moreover, Rogness and Larock demonstrated a convenient method for the synthesis of acridines from commercially available 2-aminoaryl ketone with aryne [90]. Moreover, SCHEME 60 Reaction of aryne with salicylaldehydes [84].…”

“…employing N-arylbenzamides as the coupling partner for arynes, instead of o-halobenzamides, resulted in the formation of acridines when the reaction was carried out in the presence of TBAT in toluene followed by BF 3 ·Et 2 O treatment. SCHEME 65 Synthesis of acridines arynes and 2-aminoaryl ketones [90]. Moreover, Rogness and Larock demonstrated a convenient method for the synthesis of acridines from commercially available 2-aminoaryl ketone with aryne [90].…”

4.09 Nucleophilic Coupling with Arynes

“…The versatility of the annulation method has been further improved by employing 2-(trimethylsilyl)aryl triflates as an aryne precursor: variously substituted xanthones 67, thioxanthones 68, and acridones 69 are facilely available from benzoates having a nucleophilic heteroatom (O, S, or N) at the ortho-position (Scheme 60), 197,198 and replacement of the electrophilic ester moiety into acyl, 199 formyl, 200 or electron-deficient alkenyl 201 group enhances the molecular diversity of the resulting six-membered heterocycles (Scheme 61).…”