This dissertation is separated into two parts according to the two major distinct research projects. In Part I, the full account of synthetic studies toward C10-functionalized lycopodium alkaloids is described. In Part II, the detailed discussion on the exploration of the Pummerer cyclization methodology and its application to the total...
More than 30 members of the diverse amphidinolide family of biologically active macrolides have been isolated over last three decades. From this family, amphidinolides C and F stand among the most complex and densely functionalized affiliates. Recently, we have accomplished the first total synthesis of amphidinolide F. The all-carbon framework...
Bromoalkoxylation of dihydropyran with bromine and 1-borneol, followed by dehydrobromination and epoxidation, afforded trans-2-1- bornyloxy-3,4-epoxytetrahydropyran as a major product. This was treated with sodium phenylselenide to give a 1:1 mixture of (2R,3R,4R)- 2-1-bornyloxy-3-hydroxy-4-phenylselenotetrahydropyran and its (2S,3S, 4S) diastereomer. Elimination of the selenoxide, derived from oxidation of the former with hydrogen...
Studies towards the total synthesis of (+)-Phomactin A (1), D (6), and G (9), fungal metabolites with unique molecular architecture and pronounced biological activity, are described. These studies resulted in the synthesis of advanced intermediates 354 and 356, which contain all of the carbon atoms of 1, 6 and 9....
Studies of anisotropic and isotropic Raman line shape yield information about the rotational motion (rotational correlation function) and non-reorientational (vibrational) lifetimes. The rotational motion of carbon disulfide has been studied previously by the techniques of Raman spectroscopy (6, 43), Rayleigh scattering (43, 46) and direct measurement (47). This work was...
This thesis describes the development of a new enantioselective synthetic method employing chiral cis-2,5-diaminobicyclo[2.2.2]octane-based organometallic catalysts. The significance of this new method to organic synthesis is illustrated with preparation of enantioenriched products that are transformed to important pharmaceutical agents. Chapter 1 provides a brief historical overview of asymmetric catalysis, especially...
In situ, reduction of Cp*ReO₃ by PPh₃ to form (Cp*ReO)₂(μ-O)₂ allows catalytic deoxygenation of epoxides, however, conproportionation between Reⱽ and Reⱽᴵᴵ species to form clusters of ((Cp*Re)₃(μ-O)₆}²⁺(ReO₄⁻)2 and new compound {(Cp*Re)₃(μ²-O)₃(μ³-O⁾³ReO₃}⁺(ReO₄⁻) leads to removal of rhenium from the catalytic cycle and loss of activity, The epoxide deoxygenation mediated by (Cp*ReO)₂(μ-O)₂...
Lycopodium alkaloids have shown widespread and noteworthy biological activity, consisting of over 250 known natural products. Moreover, their structural complexity and diversity have attracted considerable attention from numerous laboratories including our own. Recently, we have developed a unified approach that would provides access to numerous, previously unprepared C₁₀-functionalized lycopodium alkaloids....
The enantioselective total synthesis of quinolizidine-containing natural product cermizine D and formal syntheses of senepodine G and cermizine C has been achieved. These natural products are members of the lycopodium alkaloids, which have attracted significant attention due to their exciting biological activities and the diverse structural scaffolds. Key steps in...