A Chiral Rhodium Carboxamidate Catalyst for Enantioselective C−H Amination
作者:David N. Zalatan、J. Du Bois
DOI:10.1021/ja8031955
日期:2008.7.1
Rh2(S-nap)4, a chiraldirhodium tetracarboxamidate complex, has been developed and shown to be an effective catalyst for the asymmetric, intramolecular C-H amination of sulfamate esters. Enantiomeric excesses range from 60-99% for a collection of disparately substituted 3-arylpropylsulfamates. In addition, Rh2(S-nap)4 is found to promote chemoselective allylic C-H oxidation of unsaturated sulfamates, a property
A manganese catalyst for highly reactive yet chemoselective intramolecular C(sp3)–H amination
作者:Shauna M. Paradine、Jennifer R. Griffin、Jinpeng Zhao、Aaron L. Petronico、Shannon M. Miller、M. Christina White
DOI:10.1038/nchem.2366
日期:2015.12
is an outlier to the reactivity–selectivity paradigm. It is unique in its capacity to functionalize all types of C(sp3)–H bond intramolecularly, while displaying excellent chemoselectivity in the presence of π functionality. Mechanistic studies indicate that [Mn(tBuPc)] transfers bound nitrenes to C(sp3)–H bonds via a pathway that lies between concerted C–H insertion, observed with reactive noble metals
A Diruthenium Catalyst for Selective, Intramolecular Allylic C–H Amination: Reaction Development and Mechanistic Insight Gained through Experiment and Theory
作者:Mark Edwin Harvey、Djamaladdin G. Musaev、J. Du Bois
DOI:10.1021/ja203576p
日期:2011.11.2
tetrakis(2-oxypyridinato)diruthenium(II,III) chloride, [Ru(2)(hp)(4)Cl], catalyzes intramolecularallylic C-H amination with bis(homoallylic) sulfamate esters. These results stand in marked contrast to reactions performed with dirhodium catalysts, which favor aziridine products. The following discussion constitutes the first report of C-H amination using complexes such as [Ru(2)(hp)(4)Cl] and related diruthenium adducts
A mechanistic analysis of the Rh-catalyzed intramolecular C–H amination reaction
作者:Kristin Williams Fiori、Christine G. Espino、Benjamin H. Brodsky、J. Du Bois
DOI:10.1016/j.tet.2008.11.073
日期:2009.4
A detailed mechanistic investigation of the intramolecular dirhodium tetracarboxylate-catalyzed sulfamate ester C-H amination reaction is presented. These studies provide support for the formation of a sulfamate-derived iminoiodinane, which reacts rapidly with the rhodium catalyst to generate a nitrenoid-type oxidant. Reactivity patterns, Hammett analysis, kinetic isotope measurement, and a cyclopropane clock experiment are indicative of a concerted, asynchronous transition structure in the product-determining C-H insertion event. (C) 2008 Published by Elsevier Ltd.
GENERAL CATALYST FOR C-H FUNCTIONALIZATION
申请人:The Board of Trustees of the University of Illinois
公开号:US20160272662A1
公开(公告)日:2016-09-22
The invention provides novel manganese catalysts such as [Mn(
t
BuPc)], which are general for the amination of all types of C(sp
3
)-H bonds (aliphatic, allylic, propargylic, benzylic, ethereal), including strong 1
o
aliphatic C—H bonds, while achieving excellent chemoselectivity, stereospecificity, and high functional group tolerance. We demonstrate the late-stage diversification of bioactive complex molecules that encompass the range of C(sp
3
)-H bond types, such as selective 1
o
C—H aminations of betulinic acid and pleuromutilin derivatives. The catalysts' unprecedented balance of reactivity and selectivity is in part attributed to its mechanism of C—H amination that lies between stepwise and concerted.