Regioselective Addition Reaction of Lithium Enolates to Thio-Substituted 1,4-Naphthoquinones. Convenient Synthesis of a Naphthofuran-4,9-dione Ring System

Abstract

The regioselective addition of lithium enolates to thio-substituted 1,4-naphthoquinones gave alkylated 1,4-naphthoquinones via 1,4-addition products. A phenacyl 1,4-naphthoquinone was cyclized to a naphthofuran-4,9-dione ring system.

Design of Anti-infectious Agents from Lawsone in a Three-Component Reaction with Aldehydes and Isocyanides

“…16−18 We can also refer to two other synthetic approaches using either 3-iodolawsone 19 or thio-substituted 1,4-naphthoquinone. 20 Lawsone seems to be an important fragment while searching for antimalarial agents. Atovaquone (7) (Figure 2) 21 is reported to be the leading drug interacting with the cytochrome bc1 complex, a specific mitochondrial target of P. falciparum.…”

“…Due to their pharmacological activities, many synthetic efforts have been dedicated to their preparation. Two main synthetic routes have been adopted: (i) reaction of 2,3-dichloro-1,4-naphthoquinone with 1,3-dicarbonyl reagents and (ii) strategies based on the [3 + 2] annulation of 2-hydroxy-1,4-naphthoquinone with various reagents. − We can also refer to two other synthetic approaches using either 3-iodolawsone or thio-substituted 1,4-naphthoquinone …”

“… 16 − 18 We can also refer to two other synthetic approaches using either 3-iodolawsone 19 or thio-substituted 1,4-naphthoquinone. 20 …”

A Direct One-Pot Synthesis of Naphtho[2,3- b ]furan-4,9-dione Derivatives via C,O-Dialkylation of β-Dicarbonyl Compounds by 2,3-Dichloro-1,4-naphthoquinones

“…6 They have been synthesized from 2,3-dichloro-1,4-naphthoquinone by base catalyzed condensation with 1,3-dicarbonyl compounds, 7 from 2-hydroxy-1,4-naphthoquinone by different [3+2] annulation strategies -by thermal cyclization with enamines, 8 photochemical cycloaddition with alkenes and alkynes, 9 CAN mediated cycloaddition with alkenes and alkynes, 10,11 with 1,3-dicarbonyl compoumds 12a and 2,3-dimethoxy-1,3-butadiene, 12b base promoted reaction with 3,4-dibromo-2butanone 13 and reaction with alkynyl(phenyl)iodonium tetrafluoroborate via tandem O-Michael-carbene insertion. 14 They were also synthesized from 2-hydroxy-3iodo-1,4-naphthoquinone or 3-phenyliodonio-1,2,4-trioxo-1,2,3,4-tetrahydronaphthalenides by palladium catalyzed heteroannulation with terminal alkynes, 15 from 2,3dihydronaphtho [2,3-b]furan by formylation, oxidation and dehydrogenation, 16 from benzofuranquinone by Diels-Alder cycloaddition with butadiene and subsequent dehydrogenation, 17 from thio-substituted 1,4-naphthoquinone by regioselective addition with enolate, 18 and from 2-lithiofuran by reaction with phthalic anhydride followed by intramolecular Friedel-Crafts acylation reaction. 19 However, a survey of these present methods showed that simple one-pot syntheses from easily available starting materials with good yields and a wide applicability are still few.…”