Go to  Advanced Search

Strategies towards carbon-carbon bond formation via tandem hydrothiolation/Kumada cross-coupling

Show full item record

Files in this item

Files Size Format Description   View
ubc_2008_fall_sabarre_anthony.pdf 1.893Mb Adobe Portable Document Format   View/Open
 
Title: Strategies towards carbon-carbon bond formation via tandem hydrothiolation/Kumada cross-coupling
Author: Sabarre, Anthony
Degree Master of Science - MSc
Program Chemistry
Copyright Date: 2008
Publicly Available in cIRcle 2009-03-02
Abstract: Using recently developed methodology from our group, a variety of aryl and aliphatic terminal alkynes were reacted with n-propanethiol to undergo catalytic alkyne hydrothiolation in the presence Tp*Rh(PPh₃)₂ The alkynes examined afforded the branched isomer with high regioselectivity and moderate-to-high yield. Unsubstituted aryl alkynes, or those containing an electron-donating substituent at the para position, gave the branched vinyl sulfide in good isolated yield. In contrast, vinyl sulfides derived from aryl alkynes containing an electron-withdrawing substituent at the para position showed a decrease in reactivity and yield. The aliphatic alkynes that were investigated gave the desired branched vinyl sulfide in good yield. The isolated vinyl sulfides were then subjected to Kumada cross-coupling in the presence of NiCl₂(PPh₃)₂ with various aryl and aliphatic Grignard reagents, affording the corresponding 1,1 -disubstituted olefins. While benzyl-, phenyl- and trimethylsilylmagnesium halides were shown to be suitable cross-coupling partners, phenylethynyl-, vinyl- and n-butylmagnesium halides were not. Once the viability for the Kumada cross-coupling of vinyl sulfides was established, a one-pot protocol was investigated. It was shown that the one-pot procedure afforded the desired 1,1 -disubstituted olefin from readily available terminal alkynes in similar, and in some cases superior, yields than the two-step process.
URI: http://hdl.handle.net/2429/5327

This item appears in the following Collection(s)

Show full item record

All items in cIRcle are protected by copyright, with all rights reserved.

UBC Library
1961 East Mall
Vancouver, B.C.
Canada V6T 1Z1
Tel: 604-822-6375
Fax: 604-822-3893