Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/3339
Title: Syntheses of ferrocene-motif N-P/S mixed-donor ligands and their applications in construction of chiral carbon-carbon and carbon-heteroatom bonding via asymmetric allylic substitutions
Authors: Lam, Fuk-loi
Keywords: Hong Kong Polytechnic University -- Dissertations
Asymmetric synthesis
Catalysis
Chirality
Issue Date: 2008
Publisher: The Hong Kong Polytechnic University
Abstract: P/S chelating mixed-donor ligands have attracted recent attention in synthetic applications and showed excellent results in several asymmetric catalyses, such as transition-metal-catalyzed asymmetric allylic substitutions (AAS), asymmetric hydrogenation and aza-Diels-Alder reaction etc. In this thesis, we have designed and synthesized a family of newly developed fine-tunable phosphinamidite-thioether ligands with a ferrocene motif, which are easily accessible from the readily available Ugi amine as a chiral building block. The class of ferrocenyl phosphinamidite-thioether ligands is named as (S,pR)-FerroNPS which reflects its characteristic scaffold, chelating moiety, chirality on central and planar asymmetry. The transition-metal-catalyzed asymmetric allylic substitutions (AAS) have become one of the most powerful tools for the enantioselective formation of carbon-carbon and carbon-heteroatom bonds due to its versatile variation of nucleophiles. The family of (S,pR)-FerroNPS ligands have been successfully applied in the palladium-catalyzed asymmetric allylic alkylation (AAA) as the prototypical reaction to evaluate their usefulness leading to excellent isolated yield and enantiomeric excess in up to 99%. In a similar vein, the use of a mono-fluorinated nucleophile, a potential biologically active functionality, gave the corresponding optically active product in up to 93% ee. In addition to carbon-carbon bond formation, various amines were examined to afford the desired products containing a carbon-nitrogen bond in excellent yields and enantioselectivities (up to 96%). There are very limited cases in which the enantioselective version of palladium-catalyzed C-O bond formation has been accomplished by an allyic substitution protocol. It has been demonstrated that our Pd-(S,pR)-FerroNPS catalysts are generally effective and versatile to achieve C-O bond forming reaction with up to 96% ee. Significantly, hitherto unreported electronic effect of non-conjugated substituents on benzylic alcohols on enantioselectivity was observed.
Description: xvii, 255 leaves : ill. ; 30 cm.
PolyU Library Call No.: [THS] LG51 .H577P ABCT 2008 Lam
URI: http://hdl.handle.net/10397/3339
Rights: All rights reserved.
Appears in Collections:Thesis

Files in This Item:
File Description SizeFormat 
b22392257_link.htmFor PolyU Users 161 BHTMLView/Open
b22392257_ir.pdfFor All Users (Non-printable) 8.36 MBAdobe PDFView/Open
Show full item record

Page view(s)

445
Last Week
2
Last month
Checked on Jan 22, 2017

Download(s)

477
Checked on Jan 22, 2017

Google ScholarTM

Check



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.