Synthetic Studies Toward The Total Synthesis Of Nahuoic Acids Cii And Dii
As part of the continued synthetic campaign targeting the bioactive natural products in the Smith Laboratory, the dissertation herein describes the studies toward the total synthesis of nahuoic acids Cii and Dii, two polyol polyketide congeners that were isolated in culture from a tropical marine microorganism Streptomyces sp.. Their architecture features a densely functionalized cis-decalin core affixed to a polyol polyketide side chain which holds considerate promise to showcase Anion Relay Chemistry (ARC) - a focal point of research in the Smith group over the years. Our diversity-oriented approach entails an asymmetric Diels-Alder reaction to provide access to the common decalin intermediate, Type I and Type II ARC to rapidly assemble two alkyne side chains of different lengths and a strategic Micalizio alkene-alkyne reductive coupling tactic to unite the two fragments. Accordingly, the convergent blueprint proved to be a proof of concept in construction of the backbone of the two natural products. However, the inherent reluctance of the vinyl group to engage in a critical late-stage functionalization prevented us from putting the two nahuoic acids within reach. The above unfortunate outcome, despite considerable experimentation in the cross metathesis-based endgame, led us to reevaluate the synthetic route. Current synthetic efforts hinge upon the late-stage functionalization of an alkynyl moiety to the unsaturated carboxylic acid.