The Second-Generation, Gram-Scale Total Synthesis of (+)-Gliocladin C and The First Total Syntheses of (+)-Plectosphaeroic Acids B and C | Posted on:2014-01-13 | Degree:Ph.D | Type:Thesis | University:University of California, Irvine | Candidate:Jabri, Salman Yojiro | Full Text:PDF | GTID:2451390005490138 | Subject:Chemistry | Abstract/Summary: | | In Chapter 1, epipolythiodioxopiperazine (ETP) natural products are introduced. Focus is directed toward the subclass of tryptophan-derived ETPs and a closely related trioxopiperazine natural product, (+)-gliocladin C, which is proposed to serve as a common synthetic precursor of these ETPs. A review of previous synthetic approaches to ETP toxins is provided, and recent total syntheses of (+)-gliocladin C are described.;In Chapter 2, the development of the second-generation, gram-scale total synthesis of (+)-gliocladin C is described. The convergent route features two key steps. The first is a catalytic, enantioselective O- to C-carboxyl transfer reaction that constructs the all-carbon quaternary stereocenter of an oxindole precursor. The second is a demanding aldol condensation, which in conjunction with an N-acyliminium ion cyclization, unites two advanced intermediates of matched polarity.;In Chapter 3, the first total syntheses of plectosphaeroic acids B and C are described. A late-stage copper-mediated cross-coupling is used to forge the congested, central C&ndashN bond linking the two fragments of these natural products. Critical to the success of these syntheses is the elaboration of the di-(tert-butoxycarbonyl) derivative of gliocladin C to intermediates poised for introduction of the epipolythio- or dimethylthio functionality of these ETP natural products. | Keywords/Search Tags: | Natural products, ETP, Total syntheses, -gliocladin, First | | Related items |
| |
|