Divergent Total Syntheses of Rhodomyrtosones A and B

Herein,
we report total syntheses of the tetramethyldihydroxanthene
natural product rhodomyrtosone B and the related bis-furan β-triketone
natural product rhodomyrtosone A. Nickel-(II)-catalyzed 1,4-conjugate
addition of an α-alkylidene-β-dicarbonyl substrate was
developed to access the congener rhodomyrtosone B, and oxygenation
of the same monoalkylidene derivative followed by cyclization was
employed to obtain the bis-furan natural product rhodomyrtosone A.