The Oxidation of Maleopimaric Acid with Alkaline Permanganate^1,2

Abstract

Chemical and nuclear magnetic resonance studies were used to show that the major product, A (C^EgA),) obtained in the alkaline permanganate oxidation of maleopimaric acid has the structure V and not the structures previously suggested.A second product isolated in this oxidation has been shown to have structure IX. Further oxidation of A gave a dihydroxylactone diacid for which the revised structure VIII is proposed. Maleopimaric acid gave a crystalline bromolactone, XI. The absolute configuration of V is given.

Synthetic studies with Pinus elliottiis rosin derivatives. Oxidation of maleopimaric anhydride methyl ester and trimethyl fumaropimarate

“…Thus we decided to follow the literature suggestion 11 to carry out the ozonolysis of 1 at 0 o C in CH 2 Cl 2 solution in the presence of tetracyanoethylene (TCNE) in attempt to minimize the formation of the undesired products obtained previously by Zalkow 4,6,7 and Halbrook 8 . Although in this case the mechanism is not clear, the catalytic action of TCNE on the alcoholysis of epoxides is well known due to its π-acid and one-electron acceptor properties 12 .…”

“…IR spectra were measured on FT IR Perkin-Elmer 16 PC. Optical On the other hand, epoxide 7 was the only product isolated from the ozonolysis of 1, in the absence of tetracyanoethylene (-78 o C; CH 2 Cl 2 , 20% yield), after treatment with Me 2 S. An intractable mixture was obtained when the reaction mixture was treated with NaBH 4 or Zn/HOAc. The reaction of 1 with RuO 4 (25 o C; CH 2 Cl 2 ; NaIO 4 / RuCl 3 ) 16,17 also gave the epoxide 7 in 10% yield and did not cleave the ∆ 13 double bond to the corresponding keto-acid.…”

“…Oxidation of 1 and 2 with KMnO 4 4,5 , RuO 4 and O 3 6-8 has been already studied during the establishment of the correct stereochemistry of the Diels-Alder products. As part of our research program on the use of Pinus elliottiis' rosin as chiral synthons 9 , we prepared 1 and 2 in order to cleave the ∆ 13 double bond using different conditions.…”

The Stereochemistry of Maleopimaric Acid and the Long Range Shielding Effect of the Olefinic Bond

“…This problem, however, has been answered by the observation (17,20) that a number of lactones may be prepared from 11, for example, XV, XVII, XVIII, and X X . The formation of these derivatives requires an interaction of the anhydride grouping and the double bond, and only in the endo isomer, 11, are these groups suitable oriented.…”

“…Compound XV was obtained by alkaline permanganate oxidation of maleopimaric acid (16). The structure of this oxidation product has recently been established independently by Zalkow, Ford, and Kutney (17). The oxide X X was prepared by ozonization of XV.…”