Willian Feld (Advisor), Eric Fossum (Committee Chair), Kenneth Turnbull (Committee Member)
Master of Science (MS)
Haplomyrtin, a 1-aryl-2,3-naphthalide lignan obtained from Turkish Haplophyllum myrtifolium and Haplophyllum telephioides offers a number of synthetic challenges with the incorporation of two aromatic hydroxyl groups at positions C4 and C7 on the naphthalene ring system and regiospecific condensation of the γ-lactone ring. Improvements towards the total synthesis of haplomyrtin were pursued with commercially available vanillin and piperonal in a total of 8 separate steps. All steps have excellent reproducibility. This strategy includes bromination of protected vanillin to yield 2-(4-(4-methoxybenzyloxy)-2-bromo-5-methoxyphenyl)-1,3-dioxolane and 2-(4-(benzyloxy)-2-bromo-5-methoxyphenyl)-1, 3-dioxolane in 48% and 88% yield respectively, and incorporation of the fully functionalized pendant aryl ring through a lithium-halogen exchange followed by coupling with piperonal. The C4 hydroxyl group is placed by the in-situ formation of an isobenzofuran and subsequent Diels-Alder reaction with DMAD to yield the diester precursor to haplomyrtin, Dimethyl 1-(benzo[d][1,3]dioxol-5-yl)-7-(benzyloxy)-4-hydroxy-6-methoxynaphthalene-2,3-dicarboxylate, in 52% yield.
Department or Program
Department of Chemistry
Year Degree Awarded
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