Synthesis of Seleno-Dibenzocycloheptenones/Spiro[5.5]Trienones by Radical Cyclization of Biaryl Ynones

Abstract

We report herein an alternative method for the synthesis of seleno-dibenzocyclo­heptenones and seleno-spiro[5.5]­trienones through the radical cyclization of biaryl ynones in the presence of diorganyl diselenides, using Oxone as a green oxidizing agent. The reactions were conducted using acetonitrile as the solvent in a sealed tube at 100 °C. The protocol is operationally simple and scalable, exhibits high regioselectivity, and allows the synthesis of 24 dibenzocyclo­heptenones/spiro[5.5]­trienones in yields of up to 99%, 17 of which are unpublished compounds. Additionally, synthetic transformations of the prepared compounds, such as oxidation and reduction reactions, are demonstrated.

Radical cyclization of alkynyl aryl ketones for the synthesis of 3-seleno-substituted thiochromones and chromones

“…Based on the results of the control experiments and previous reports, 21 a plausible mechanism was proposed, as shown in Scheme 3. The first step is the formation of HO˙ and SO 4 ˙ − from the dissociation of Oxone®, generated from potassium peroxymonosulfate (KHSO 5 ).…”

Access to Diverse Seleno-spirocyclohexadienones via Ag(II)-Catalyzed Selenylative ipso-Annulation with Se and Boronic Acids

“…The Ag­(II)-catalyzed oxidative selenylative ipso -annulation was further expanded to the biaryl ynones holding 4-OMe group on distal phenyl ring to obtain spiro[5.5]­trienones (Scheme ). The spiro[5.5]­trienones are key structural motifs present in diverse biologically active molecules. , To best of our knowledge, there are only two methods available in the literature to access selenylated spiro[5.5]­trienones using diselenide as selenium source. , Hence, the present protocol employing Se powder in the presence of boronic acid will be attractive for the assembly of various seleno-spiro[5.5]­trienones. Agreeably, the reaction of 6a with phenyl boronic acid ( 2a ) under the optimal reaction conditions led to seleno-spiro­[5,5]­trienone 7a in 90% yield.…”

“… 16 , 17 To best of our knowledge, there are only two methods available in the literature to access selenylated spiro[5.5]trienones using diselenide as selenium source. 15b , 18 Hence, the present protocol employing Se powder in the presence of boronic acid will be attractive for the assembly of various seleno-spiro[5.5]trienones. Agreeably, the reaction of 6a with phenyl boronic acid ( 2a ) under the optimal reaction conditions led to seleno-spiro[5,5]trienone 7a in 90% yield.…”

Synthesis of Spiro[5.5]trienones- and Spiro[4.5]trienones-Fused Selenocyanates via Electrophilic Selenocyanogen Cyclization and Dearomative Spirocyclization

“…At present, considerable efforts have been directed toward the preparation of selenocyanates, such as the nucleophilic substitution of KSeCN, selenocyanate salts with oxidants (CAN, TBHP) system, and electrocatalytic selenocyanation with KSeCN etc . Lately, the synthesis of spirocyclic compounds by the radical reactions has been developed by Reddy’s, Perin’s, and Cui’s group, respectively. However, only seleno-spirocyclic compounds can be obtained through these methods, which could not construct the spiro -fused selenocyanates.…”