Allylboration reactions have been thoroughly utilized in organic chemistry since it was discovered that they could add in a nucleophilic fashion to aldehydes and ketones in 1964. Modification of allylboronates and the substrates that they can react with has been the focus of many research groups over the past three decades. Recent works have made use of catalysis to promote the addition of allylboronates that are generally otherwise unreactive toward various electrophiles. Chapter 2 will discuss the discovery that Brnsted acids can catalyze the addition of unreactive 2-alkoxycarbonyl allylboronates to aldehydes and that the diastereoselectivity of the reaction is determined by the electronic nature of the aldehyde. Ketones and imines are much less reactive than aldehydes towards allylboronates due to steric and electronic factors. As a result, new conditions are often required to promote the allylboration reaction of ketones and imines. Chapter 3 will briefly discuss the challenges that ketones present as substrates for allylboration reactions and show my attempts at achieving this transformation. Chapter 4 will describe imines and their associated challenges as substrates for allylboration reactions. However, once harnessed, these substrates provide easy access to -methylene -lactones when a 2-alkoxycarbonyl allylboronate is used as the allylating reagent. The modification of important or interesting molecules by making major or minor changes to a common core structure is the basis of diversity-oriented synthesis of combinatorial libraries. -Alkylidene -lactones and -alkylidene -lactams are biologically interesting compounds present in numerous natural products. Chapter 5 will discuss how the title compounds were modified by various metal-catalyzed coupling reactions to provide a diversity-oriented combinatorial library of -lactones and -lactams. Since -lactones are prevalent in many natural products, the application of 2-alkoxycarbonyl allylboronates to a target-oriented synthesis was intriguing. Unlike diversity-oriented synthesis, target oriented synthesis aims at synthesizing a single compound through any number of controlled steps, arriving at one specific product that is obtained as a pure isomer. Access to highly complex -lactones is often tedious, however, Chapter 6 will discuss how a simple, one-step allylboration reaction of a complex aldehyde with a 2-alkoxycarbonyl allylboronate can lead to a highly substituted -lactone. This -lactone can be further modified and transformed into chinensiolide B, a biologically active natural product isolated from a plant found in various locations in China.

No description available.

No description available.

Written for the Dept. of Chemistry. Title from title page of PDF (viewed 2009/06/11). Includes bibliographical references.

Thesis (Ph. D.) -- California Institute of Technology, 2010. / Title from home page (viewed 03/25/2010). Advisor and committee chair names found in the thesis' metadata record in the digital repository. Includes bibliographical references.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references (leaves 247-267). Also available in electronic version. Access restricted to campus users.

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xv, 151 p.; also includes graphics. Includes bibliographical references (p. 134-151). Available online via OhioLINK's ETD Center

No description available.

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (leaves 120-127).

Indiana University-Purdue University Indianapolis (IUPUI) / A novel route has been developed for the solid-phase synthesis of N-carboxyalkyl unnatural amino acids as potential metalloprotease inhibitors. The key step involves a nitrogen alkylation of resin-bound amino acids with -bromoesters. Alkylation of the benzophenone imine of glycine on Wang resin was used to introduce unnatural amino acid side chains onto the resin-bound glycine. The benzyl -bromoesters [BrCH(R2)CO2Bn], starting materials for the C-N bond construction, were prepared in solution by diazotization of naturally-occurring amino acids to form the -bromoacids, followed by benzylation of the carboxylic acid to form the benzyl -bromoesters. N-Alkylation of the resin-bound, unnatural amino acids with the benzyl -bromoesters and subsequent cleavage from resin gave the benzyl ester monoacid intermediates. Exploration of reverse-phase cyano-silica gel chromatography and preparative liquid chromatography provided effective purification of the benzyl ester intermediates. Hydrolysis of the analytically pure benzyl ester monoacids afforded clean products as the diacids. The two points of variation introduced through the two on-resin alkylation steps, C-alkylation of the benzophenone imine of glycine and N-alkylation with the benzyl -bromoesters, allow for the combinatorial synthesis of a library of target compounds.