Synthetic Transformation of Abietic Acid IIa. Oxidation of Diene Adducts

Abstract

The diene adduct of 2-chloroacrylonitrile and abietic acid (1) can be converted to tetracyclic ketone 2. Oxidation of 1 and 2 with ozone, KMnO 4 , OsO 4 , and tert-butylchromate are described. Three products have been further oxidized by Baeyer-Villiger reactions.

Synthetic Transformation of Abietic Acid IIIa. Photoconversion of Diene Adducts

“…After three days, only resin acids could be detected. ÐÐÐÐ a For part I see [1], for part II see [2].…”

“…In previous publications we have described the synthesis of ,-enone 1 by DielsAlder addition of 2-chloroacrylonitrile to abietic acid methyl ester and subsequent treatment of the adduct with NaOH [1,2]. ,-Enones have two chromophores and are capable of undergoing a variety of photochemical reactions, e.g.…”

Diterpenoids (1998)

“…78 The Friedel-Crafts acylation and deisopropylation of methyl dehydroabietate has been described. 79 A number of investigations have been reported [80][81][82] into the chemistry of the Diels-Alder adducts of abietic acid and into the oxidation of rings B and C. 83 5 Tetracyclic diterpenoids…”

An Efficient Oxyfunctionalization of Quinopimaric Acid Derivatives with Ozone

“…Oxyfunctionalization of natural products is an effective method to obtain new biologically active compounds or valuable chiral building blocks for drug synthesis [13]. Oxidative transformations of levopimaric acid diene adducts, such as maleopimaric, fumaropimaric and quinopimaric acids, involved hydrogen peroxide [11,14], peracids [15], ozone [16 -18], osmium tetroxide, tertbutyl chromate [19] and permanganate oxidation [20]. The endoconfiguration of most Diels-Alder adducts appears to complicate access to the bridging double bond for common oxidizing agents.…”