| The first part of this work describes the studies toward the stereoselective synthesis of calphostin D. Two routes involving chiral tethers were investigated. The first route involved the construction of the tether between the oxygen moieties at the C6 and C7 positions. A variety of routes were attempted but were ultimately unsuccessful. The second route involved the construction of the tether between the C1 and C12 positions. Due to difficulties introducing the chiral centers on the tether, this route was also unsuccessful.; The second part was the total synthesis of (±) methyl PD 116740, an angucyclinone antibiotic. The first key step of the synthesis involved the condensation of phthalide sulfide 2.23 with orthoquinone monoketal 2.20 to provide the desired angular ring system. Later in the synthesis, the use of Harvey's procedure reduced the orthoquinone 2.31 to the desired 5,6-dihydroxy moiety present in PD 116740.; The final part of this work involved the design and synthesis of a novel chromanone for the synthesis of xanthone antibiotics. Based of the known phthalide sulfone 3.6, the chromanone 3.19 was successfully prepared. The anion of 3.19 was then condensed with a variety of Michael acceptors to prepare the basic ring structure of a number of xanthanone antibiotics. |
