Copper(ii)-catalyzed oxidative ipso-annulation of N-arylpropiolamides and biaryl ynones with 1,3-diketones: construction of diketoalkyl spiro-trienones

Abstract

An unprecedented copper-catalyzed ipso-annulation reaction of N-(p-methoxyaryl)propiolamides with 1,3-diketones has been developed, which enables the assembly of diketo-alkylated spiro[4.5]trienones involving oxidative dearomatization in the presence of ammonium persulfate [(NH4)2S2O8] as...

Visible Light Promoted Brominative Dearomatization of Biaryl Ynones to Spirocycles

“…Inspired by the primary results of this photocatalytic oxidation of biaryl ynones, we next took the challenge of implementation of this strategy to other ynone systems (4). 21 Biphenyl N-arylpropiolamides are susceptible to exhibit synthetic versatility in radical chemistry and theoretically capable to undergo [1,1], [1,2], [1,5], and [2,5] cyclizations; some of the possibilities are designed in Figure 4 and details in Supporting Information. This diverse nature of the substrate in radical reaction condition prompted us to study the viability of the present annulation reaction.…”

Synthesis of Indenones via Persulfate Promoted Radical Alkylation/Cyclization of Biaryl Ynones with 1,4-Dihydropyridines

“…To date, the cyclization of alkynes toward the synthesis of cyclic compounds has been effectively investigated [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Recently, the radical cascade cyclization of biaryl ynones has been demonstrated to be a useful approach to construct six-membered spiro[5,5]trienones [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ] with the development of different types of radical precursors ( Scheme 1 a–c). For example, Chen and Zhou reported an iron-catalyzed cascade silyl radical addition/6- exo -trig cyclization/dearomatization of biaryl ynones with silane, affording silylated spiro[5.5]trienones in good yields [ 35 ].…”

“…For example, Chen and Zhou reported an iron-catalyzed cascade silyl radical addition/6- exo -trig cyclization/dearomatization of biaryl ynones with silane, affording silylated spiro[5.5]trienones in good yields [ 35 ]. In addition, several groups have demonstrated some elegant examples based on C-, N-, P-, S-, Si-, Se-centered radicals-induced cascade cyclization of biaryl ynones in the presence of transition-metal catalysts, oxidants or photocatalysts [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ]. For example, Duan and Yang reported the preparation of alkyl-functional spiro[5.5]trienone through alkylative dearomatization and the spirocyclization of biaryl ynones, respectively [ 29 , 33 ].…”

Radical-mediated sulfonylative/thiolative cyclization of biaryl enones to phenanthrone derivatives

“…Considering the importance of radical cascade reactions in establishing different reaction pathways, 6 the design of different substrates would enable novel methods for the synthesis of various chemical scaffolds. Based on our work involving the cascade thiofunctionalization/annulation of alkynes and alkenes, 7 we envisaged that biaryl enones are readily accessible and can act as radical acceptors followed by an intramolecular annulation with the aryl ring to provide phenanthrones. In a similar manner, recently, Li's research group reported an approach for the preparation of fluoro-alkylated phenanthrene-9(10 H )-ones from biaryl vinyl ketones (Scheme 1d).…”