國立高雄大學圖資館 |

Language: English

Back

Carbon-hydrogen animation reactions ...

Espino, Christine Giselle.

Carbon-hydrogen animation reactions for organic synthesis: Discovery, scope, and mechanism.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Carbon-hydrogen animation reactions for organic synthesis: Discovery, scope, and mechanism.
Author:	Espino, Christine Giselle.
Description:	255 p.
Notes:	Adviser: Justin Du Bois.
Notes:	Source: Dissertation Abstracts International, Volume: 65-09, Section: B, page: 4575.
Contained By:	Dissertation Abstracts International65-09B.
Subject:	Chemistry, Organic.
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3145505
ISBN:	0496044486

Carbon-hydrogen animation reactions for organic synthesis: Discovery, scope, and mechanism.
Espino, Christine Giselle.

Carbon-hydrogen animation reactions for organic synthesis: Discovery, scope, and mechanism. - 255 p.

Adviser: Justin Du Bois.

Thesis (Ph.D.)--Stanford University, 2004.

The remarkable diversity of nitrogen-containing materials inspires the invention of new, versatile methods for their preparation. The development of highly efficient C-H amination protocols would enable the evolution of synthetic strategies in which densely functionalized, nitrogen-rich molecules are rapidly constructed from simple precursors. Nitrene oxidants are ideally suited for such endeavors: the chemistry of these electrophilic intermediates, however, has found limited application in synthesis due to poor reaction efficiency and product selectivities. We have identified and developed conditions in which dirhodium(II) complexes modulate the nitrene reactivity and thus enables highly efficient intramolecular amination of electronically disparate C-H bonds. The combination of amine derivatives and iodobenzene diacetate in the presence of a Rh(II) catalyst affords high yields of synthetically versatile nitrogen-containing heterocycles. These protocols enable the use of previously unprecedented functional groups as N-atom sources and thus considerably expand the synthetic impact of oxidative amination reactions. Mechanistic investigations support the formulation of a Rh-bound nitrene as the reactive oxidant and C-H insertion is a concerted, albeit asynchronous, event. Kinetics studies determined that there is no dependence on [Rh catalyst] at low product conversion but that increased catalyst loading does afford higher product conversion at late time points. 1H NMR studies revealed that catalyst speciation occurs as the reaction progresses and carboxylate slippage was proposed as a potential mechanism for degradation. To probe this hypothesis, a Rh(II) complex in which adjacent carboxylate ligands are covalently tethered was designed and synthesized. This catalyst has demonstrated higher turnover numbers as well as affording significant progress in the development of new C-H amination protocols. It is anticipated that continued efforts in methodology development, applications to total synthesis, and mechanism-driven catalyst design will enable the continued evolution of synthetically useful C-H oxidation processes.

ISBN: 0496044486Subjects--Topical Terms:

193634
Chemistry, Organic.

Carbon-hydrogen animation reactions for organic synthesis: Discovery, scope, and mechanism.
LDR:03100nmm _2200253 _450 001 162870
005 20051017073532.5
008 090528s2004 eng d
020 $a 0496044486
035 $a 00149371
040 $a UnM $c UnM
100 0 $a Espino, Christine Giselle. $3 228015
245 1 0 $a Carbon-hydrogen animation reactions for organic synthesis: Discovery, scope, and mechanism.
300 $a 255 p.
500 $a Adviser: Justin Du Bois.
500 $a Source: Dissertation Abstracts International, Volume: 65-09, Section: B, page: 4575.
502 $a Thesis (Ph.D.)--Stanford University, 2004.
520 # $a The remarkable diversity of nitrogen-containing materials inspires the invention of new, versatile methods for their preparation. The development of highly efficient C-H amination protocols would enable the evolution of synthetic strategies in which densely functionalized, nitrogen-rich molecules are rapidly constructed from simple precursors. Nitrene oxidants are ideally suited for such endeavors: the chemistry of these electrophilic intermediates, however, has found limited application in synthesis due to poor reaction efficiency and product selectivities. We have identified and developed conditions in which dirhodium(II) complexes modulate the nitrene reactivity and thus enables highly efficient intramolecular amination of electronically disparate C-H bonds. The combination of amine derivatives and iodobenzene diacetate in the presence of a Rh(II) catalyst affords high yields of synthetically versatile nitrogen-containing heterocycles. These protocols enable the use of previously unprecedented functional groups as N-atom sources and thus considerably expand the synthetic impact of oxidative amination reactions. Mechanistic investigations support the formulation of a Rh-bound nitrene as the reactive oxidant and C-H insertion is a concerted, albeit asynchronous, event. Kinetics studies determined that there is no dependence on [Rh catalyst] at low product conversion but that increased catalyst loading does afford higher product conversion at late time points. 1H NMR studies revealed that catalyst speciation occurs as the reaction progresses and carboxylate slippage was proposed as a potential mechanism for degradation. To probe this hypothesis, a Rh(II) complex in which adjacent carboxylate ligands are covalently tethered was designed and synthesized. This catalyst has demonstrated higher turnover numbers as well as affording significant progress in the development of new C-H amination protocols. It is anticipated that continued efforts in methodology development, applications to total synthesis, and mechanism-driven catalyst design will enable the continued evolution of synthetically useful C-H oxidation processes.
590 $a School code: 0212.
650 # 0 $a Chemistry, Organic. $3 193634
690 $a 0490
710 0 # $a Stanford University. $3 212607
773 0 # $g 65-09B. $t Dissertation Abstracts International
790 $a 0212
790 1 0 $a Du Bois, Justin, $e advisor
791 $a Ph.D.
792 $a 2004
856 4 0 $u http://libsw.nuk.edu.tw:81/login?url=http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3145505 $z http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3145505