A gram-scale synthesis of lachnanthocarpone

Abstract

The synthesis of lachnanthocarpone (2,6-dihydroxy-9-phenyl-1H-phenalen-1-one, 1), a powerful antioxidant from Lachnanthes tinctoria (Haemodoraceae), has been re-examined to extend the amount of material that can be prepared. Including a Buchwald hydroxylation into the synthetic plan in conjunction with microwave assistance allowed the preparation of 3.5 g of material in seven steps (22 % global yield), transforming this synthesis into the most efficient hitherto.

Keywords

• Phenylphenalenones
• Buchwald aromatic substitution
• Microwave-assisted synthesis