The Structural Elucidation of a Proposed Intermediate in the Stereoselective Synthesis of dl-Desoxypodocarpic Acid

Citation

Grand, Paul Sheldon (1969) The Structural Elucidation of a Proposed Intermediate in the Stereoselective Synthesis of dl-Desoxypodocarpic Acid. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/YBB4-6J75. https://resolver.caltech.edu/CaltechTHESIS:02222016-105427770

Abstract

The hydroxyketone C-3, an intermediate in the stereo-selective total synthesis of dl-Desoxypodocarpic acid (ii), has been shown by both degradative and synthetic pathways to rearrange in the presence of base to diosphenol E-1 (5-isoabietic acid series). The exact spatial arrangements of the systems represented by formulas C-3 and E-1 have been investigated (as the p-bromobenzoates) by single-crystal X-ray diffraction analyses. The hydroxyketone F-1, the proposed intermediate in the rearrangement, has been synthesized. Its conversion to diosphenol E-1 has been studied, and a single-crystal analysis of the p-bromobenzoate derivative has been performed. The initially desired diosphenol C-6 has been prepared, and has been shown to be stable to the potassium t-butoxide rearrangement conditions. Oxidative cleavage of diosphenol E-1 and subsequent cyclization with the aid of polyphosphoric acid has been shown to lead to keto acid I-2 (benzobicyclo [3.3.1] nonane series) rather than keto acid H-2 (5-isoabietic acid series).

Thesis Files