Total Syntheses of Roseochelins A and B Using an Oxidative Decarboxylation Strategy
Mikel J Allas1, Laura Burchill1, Adam W E Stewart1
1School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia.
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Roseochelins A and B are produced by Phaeobacter inhibens and proposed to arise from algal sinapic acid through combined enzymatic and nonenzymatic steps. We report concise, biomimetic total syntheses mirroring a revised biosynthetic pathway differing from earlier proposals in key oxidative and decarboxylative intermediates. Roseochelin A arises via spontaneous [4 + 2] dimerization of sinapic acid to thomasidioic acid, followed by metal-catalyzed oxidative decarboxylation. Roseochelin B is accessed by regioselective catechol formation, ortho-quinone-mediated thiomethylation, and late-stage metal- or photocatalyzed oxidative decarboxylation.
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