eprintid: 20815
rev_number: 16
userid: 2749
dir: disk0/00/02/08/15
datestamp: 2014-05-29 17:13:32
lastmod: 2016-11-15 14:18:14
status_changed: 2014-05-29 17:13:32
type: thesis_degree
metadata_visibility: show
contact_email: lixiben@gmail.com
item_issues_count: 0
eprint_status: archive
creators_name: Li, Xiben
creators_email: xil64@pitt.edu
creators_id: XIL64
title: Endeavors in Methodology Development and Natural Product Total Synthesis
ispublished: unpub
divisions: sch_as_chemistry
full_text_status: public
keywords: Boron-Hydrogen bond insertion, NHC-Boranes, Total synthesis, Tulearins
abstract: This thesis deals with the development of new reaction methodology, as well as total synthesis of natural products.
Chapter 1 describes readily available rhodium(II) salts catalyzed B-H insertion reactions between NHC-boranes (NHC-BH3) and diazocarbonyl compounds (N2CR1COR2). Stable α-NHC-boryl carbonyl compounds (NHC-BH2-CHR1COR2) are isolated in good yields. The reaction is a reliable way to make boron-carbon bonds with good tolerance for variation in both the NHC-borane and diazocarbonyl components. It presumably occurs by insertion of a transient rhodium carbene into a boron-hydrogen bond of the NHC-borane. Competition experiments show that a typical NHC-borane is highly reactive toward rhodium carbenes.
Chapter 2 describes the synthetic routes towards the synthesis of tulearin A and tulearin C. Large scale synthesis of the bottom fragments (C1-C12) and the top fragment (C13-C26) for tulearin A was accomplished. Different synthetic routes were tested to accomplish the total synthesis of tulearin A. Some major problems toward the total synthesis of tulearin A were identified and solved. Meanwhile a novel synthetic route towards the total synthesis of tulearin C was developed. New methodologies were applied to make the synthesis more efficient. The total synthesis of tulearin C was not accomplished because of the difficulty of removal of the acetate protecting group at C17.
date: 2014-05-29
date_type: published
pages: 182
institution: University of Pittsburgh
refereed: TRUE
etdcommittee_type: committee_chair
etdcommittee_type: committee_member
etdcommittee_type: committee_member
etdcommittee_type: committee_member
etdcommittee_name: Curran, Dennis
etdcommittee_name: Paul, Floreancig
etdcommittee_name: Wipf, Peter
etdcommittee_name: Zemaitis, Michael
etdcommittee_email: curran@pitt.edu
etdcommittee_email: florean@pitt.edu
etdcommittee_email: pwipf@pitt.edu
etdcommittee_email: maz@pitt.edu
etdcommittee_id: CURRAN
etdcommittee_id: FLOREAN
etdcommittee_id: PWIPF
etdcommittee_id: MAZ
etd_defense_date: 2014-03-07
etd_approval_date: 2014-05-29
etd_submission_date: 2014-03-24
etd_release_date: 2014-05-29
etd_access_restriction: immediate
etd_patent_pending: FALSE
thesis_type: dissertation
degree: PhD
citation:   Li, Xiben  (2014) Endeavors in Methodology Development and Natural Product Total Synthesis.  Doctoral Dissertation, University of Pittsburgh.    (Unpublished)  
document_url: http://d-scholarship-dev.library.pitt.edu/20815/1/Xiben_Li_PhD_Dissertation_2014.pdf