Palladium-catalyzed arylation of 1,4-naphthoquinones with aryl iodides and its synthetic application to the benzo[b]phenanthridine skeleton

The Different Facets of Metal‐Catalyzed C−H Functionalization Involving Quinone Compounds

“…Akagi and Komatsu reported a similar Pd‐catalysed cross‐coupling of aryl iodides with naphthoquinone in 2019 [59] . The conditions of Pd(PPh 3 ) 2 Cl 2 and AgOAc in dioxane enabled cross‐coupling of both electron‐rich and deficient aryl iodides, which was an improvement upon the conditions reported by Ding and co‐workers (Scheme 27).…”

Copper‐Catalyzed Cross‐Dehydrogenative Phosphorylation of 2‐Amino‐1,4‐naphthoquinones with H‐Phosphonates

“…In addition, Baran [16a] and Maiti [16b] independently reported the arylation of 1,4‐quinones with arylboronic acids under the catalysis of AgNO 3 or Fe(NO 3 ) 3 . Besides, Pd‐catalyzed arylation of 1,4‐quinones with (hetero)arenes [16c] or aryl iodides [16d] were developed (Scheme 1b). Recently, transition metal‐free radical alkylation of 1,4‐quinones was achieved using 1,4‐dihydropyridines (DHPs) as the alkyl [17a] .…”

Total Synthesis of Phenanthroviridin Aglycon and Its Analog

“…Recently, we reported a Pd‐catalyzed direct arylation of α,β‐unsaturated O ‐methyl oximes and 1,4‐naphthoquinones with aryl iodides [16,17] . We also successfully developed a synthetic pathway for the benzo[ b ]phenanthridine skeleton (benzo[ b ]phenanthridine‐7,12‐dione) from the resulting 2‐aryl‐1,4‐naphthoquinone [17] .…”

“…[9][10][11][12][13][14][15] Recently, we reported a Pd-catalyzed direct arylation of α,βunsaturated O-methyl oximes and 1,4-naphthoquinones with aryl iodides. [16,17] We also successfully developed a synthetic pathway for the benzo[b]phenanthridine skeleton (benzo[b] phenanthridine-7,12-dione) from the resulting 2-aryl-1,4naphthoquinone. [17] In this paper, we describe the total synthesis of phenanthroviridin aglycon (1) utilizing our method for the Pd-catalyzed direct arylation of 5-hydroxy-1,4-naphthoquinone (10) with aryl iodide 11 as a key reaction, which does not require prior functionalization of the 1,4-naphthoquinone part unlike previous approaches (Figure 2D).…”

“…The Pd-catalyzed direct arylation of 5-hydroxy-1,4-naphthoquinone (10) with aryl iodide 11 was studied next (Table 1). Based on our recent work, [17] the reaction was carried out in 1,4dioxane with silver acetate (2 equiv) as the additive in the presence of Pd(PPh 3 ) 2 Cl 2 (10 mol%) (entry 1). As a result, aryl-1,4-naphthoquinones 16 were obtained in 11% yield.…”