General and Expedient Synthesis of 1,4-Dioxygenated Xanthones

Abstract

A facile entry to 1,4-dioxygenated xanthones having a variety of substitution patterns and substituents was developed that features a novel application of the Moore cyclization using substrates that were readily assembled in a highly convergent fashion by an acetylide stitching process. The practical utility of the methodology was demonstrated by an efficient synthesis of a naturally-occurring xanthone and correction of the structure of dulcisxanthone C.

Total Syntheses of Graphisin A and Sydowinin B

“…This result supports the intermediacy of benzoquinone 21 enroute to 23 . While both 6- endo - trig and 5- exo-trig cyclization modes of 21 are possible, 33 the observed isomer 23 is likely favored due to the bisected conformation 34 of proposed intermediate 21 which places one ortho -phenol in favorable alignment with the π*-orbital of the C-7 quinone carbon (Figure 4). …”

Diastereoselective Synthesis of Complex cis-Hexahydroindanes by Reductive Alkylation

“…Starting from PMB-protected o -vanillin, (3-methoxy-2-(4-methoxy­benzyl­oxy)phenyl)methanol is available from aldehyde reduction (NaBH 4 , EtOH, 10 min, 23 °C, 96%). The resulting white solid (11.4 g, 41.7 mmol, 1.00 equiv), mp 67–70 °C, was used without purification.…”

Organosoluble xanthone-based polyimides: synthesis, characterization, antioxidant activity and heavy-metal sorption

“…Consequently, it seems to have a great potential as a structural pattern in high-performance polymers. Although several different synthetic and natural xanthones were introduced [14][15][16][17][18] few of such biologically active compounds were investigated in a polymer synthesis. 19 Polyxanthones can be used for high-temperature applications and as electrical insulating materials due to their excellent solvent and chemical resistance, good physical and electrical properties even at high temperatures.…”