Squaric acid ester-based total synthesis of echinochrome A.
The total synthesis of echinochrome A is described. Both key intermediates 5 and 8 were efficiently prepared from diisopropyl squarate 7. Nucleophilic addition of aryllithium 8 to 5, followed by thermal ring-expansion/cyclization of the 1,2-adduct 4, furnished hydroquinone 3. Oxidation and full deprotection of 3 gave the title compound.
Peña-Cabrera
Eduardo
E
Facultada de Química, Universidad de Guanajuanto, Mexico. eduardop@quijote.ugto.mx
Liebeskind
Lanny S
LS
D000818:Animals; D002384:Catalysis; D002855:Chromatography, Thin Layer; D003500:Cyclization; D003503:Cyclobutanes / Q000737:chemistry*; D004952:Esters / Q000737:chemistry; D015394:Molecular Structure; D009285:Naphthoquinones / Q000138:chemical synthesis* / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular; D012617:Sea Urchins / Q000737:chemistry*
D003503:Cyclobutanes; D004952:Esters; D009285:Naphthoquinones; C007573:echinochrome A; C030042:squaric acid