Synthetic Studies of Naphtho[2,3-b]furan Moiety Present in Diverse Bioactive Natural Products

Abstract

The preparation of several functionalized furan derivatives and attempts to transform them into a derivative containing 6H-furo[3,4-b]furanone skeleton towards the construction of naphtho[2,3-b] furan are described. Attempted Pummerer reaction of a furan sulfoxide derivative produced four interesting furan derivatives. Base promoted annulation between methyl 2-(phenylsulfinylmethyl)-3-furoate and 2-cyclohexenone proceeded to give dihydro naphtho[2,3-b]furanone derivative in a regiospecific manner.

Regiodefined synthesis of brominated hydroxyanthraquinones related to proisocrinins

“…In the next stage, Hauser annulation of cyanophthalide 12 with cyclohexenone 13 was carried out in the presence of LiO t -Bu (LTB) in THF at −60 °C to furnish quinol A [ 39 – 42 ]. Due to its sensitivity to aerial oxidation; it was directly aromatized by bubbling O 2 through its DMF solution to give anthraquinone 28 in the manner described in [ 43 ]. The acetate group in 28 was cleaved with an aqueous alkaline solution to furnish 29 in 80% yield.…”