Li Deng

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Name: Deng, Li

Organization: Brandeis University , USA

Department: Department of Chemistry

Title: (PhD)

TOPICS

Organic Chemistry

Polymer

Stimuli Responsive Polymers PH Responsive Polymers Stimuli Responsive Polymers Photo Responsive Polymers PH Responsive Polymers Temperature Responsive Polymers

Chemicals
References

Cinchonium Betaines as Efficient Catalysts for Asymmetric Proton Transfer Catalysis: The Development of a Practical Enantioselective Isomerization of Trifluoromethyl Imines

Co-reporter:Xiao Zhou, Yongwei Wu, and Li Deng

Journal of the American Chemical Society 2016 Volume 138(Issue 37) pp:12297-12302

Publication Date(Web):August 31, 2016

DOI:10.1021/jacs.6b08727

We have developed a new class of cinchonium betaine catalysts bearing both a base moiety and an aromatic moiety as an N-substituent of the quinuclidine motif. These cinchonium betaines were found to promote proton transfer catalysis with 1000–5000 turnovers per 24 h, thereby enabling us to realize highly efficient enantioselective isomerization of trifluoromethyl imines to provide a practical access to optically active trifluoromethylated amines.

Catalytic Asymmetric Synthesis of Chiral γ-Amino Ketones via Umpolung Reactions of Imines

Co-reporter:Lin Hu, Yongwei Wu, Zhe Li, and Li Deng

Journal of the American Chemical Society 2016 Volume 138(Issue 49) pp:15817-15820

Publication Date(Web):November 22, 2016

DOI:10.1021/jacs.6b09754

The first direct catalytic asymmetric synthesis of γ-amino ketones was realized by the development of a highly diastereoselective and enantioselective C–C bond-forming umpolung reaction of imines and enones under the catalysis of a new cinchona alkaloid-derived phase-transfer catalyst. In a loading ranging from 0.02 to 2.5 mol %, the catalyst activates a broad range of trifluoromethyl imines and aldimines as nucleophiles to engage in chemo-, regio-, diastereo- and enantioselective C–C bond-forming reactions with acyclic and cyclic enones, thereby converting these readily available prochiral starting materials into highly enantiomerically enriched chiral γ-amino ketones in synthetically useful yields. Enabled by this unprecedented umpolung reaction of imines, conceptually new and concise routes were developed for the asymmetric synthesis of nitrogen-heterocycles such as pyrrolidines and indolizidines.

Catalytic Enantioselective Peroxidation of α,β-Unsaturated Aldehydes for the Asymmetric Synthesis of Biologically Important Chiral Endoperoxides

Co-reporter:Lin Hu; Xiaojie Lu

Journal of the American Chemical Society 2015 Volume 137(Issue 26) pp:8400-8403

Publication Date(Web):June 23, 2015

DOI:10.1021/jacs.5b05345

We have developed an unprecedented highly enantioselective catalytic peroxidation of enals. Critical to this development is the discovery that varying the structure of the hydroperoxide has a significant impact on the enantioselectivity of the organocatalytic asymmetric peroxidation. This novel transformation enabled the development of an enantioselective route toward the core structure shared by all members of the stolonoxide family of anticancer natural products, a connected trans-3,6-disubstituted-1,2-dioxane and trans-2,5-disubstituted-tetrahydrofuran ring system. Our route also features an unprecedented cyclization cascade of a chiral bis(epoxy)hydroperoxide. The new methodology and synthetic strategy established in this work should be applicable to the enantioselective synthesis of a broad range of chiral 1,2-dioxolanes and 1,2-dioxanes, thereby facilitating biological and medicinal chemistry studies of peroxy natural products.

Catalytic asymmetric direct aldol reaction of α-alkyl azlactones and aliphatic aldehydes

Co-reporter:Yang Zheng and Li Deng

Chemical Science 2015 vol. 6(Issue 11) pp:6510-6514

Publication Date(Web):04 Aug 2015

DOI:10.1039/C5SC02116B

An unprecedented highly diastereoselective and enantioselective aldol reaction of α-alkyl azlactones and aliphatic aldehydes was achieved with cinchona alkaloid catalysts. To our knowledge, this reaction provides the first useful catalytic asymmetric access toward β-hydroxy-α-amino acids bearing alkyl substituents, which are structural motifs embedded in many natural products.

Catalytic Asymmetric Peroxidation of α,β-Unsaturated Nitroalkenes by a Bifunctional Organic Catalyst

Co-reporter:Xiaojie Lu and Li Deng

Organic Letters 2014 Volume 16(Issue 9) pp:2358-2361

Publication Date(Web):April 14, 2014

DOI:10.1021/ol500677v

A new enantioselective peroxidation of α,β-unsaturated nitroalkenes was realized with an easily accessible acid–base bifunctional organic catalyst derived from cinchona alkaloids. This reaction provides unprecedented easy access to optically active chiral peroxides, as illustrated by the asymmetric synthesis of β-peroxy nitro compounds.

Asymmetric Synthesis of Trifluoromethylated Amines via Catalytic Enantioselective Isomerization of Imines

Co-reporter:Yongwei Wu

Journal of the American Chemical Society 2012 Volume 134(Issue 35) pp:14334-14337

Publication Date(Web):August 20, 2012

DOI:10.1021/ja306771n

A new approach toward the asymmetric synthesis of optically active trifluoromethylated amines was enabled by an unprecedented, highly enantioselective catalytic isomerization of trifluoromethyl imines with a new chiral organic catalyst. Not only aryl but also alkyl trifluoromethylated amines could be obtained in high enantioselectivities.

Asymmetric Approach toward Chiral Cyclohex-2-enones from Anisoles via an Enantioselective Isomerization by a New Chiral Diamine Catalyst

Co-reporter:Jung Hwa Lee

Journal of the American Chemical Society 2012 Volume 134(Issue 44) pp:18209-18212

Publication Date(Web):October 8, 2012

DOI:10.1021/ja308623n

A 3-step asymmetric approach toward the optically active chiral cyclohex-2-enones from anisoles has been developed. The crucial asymmetric induction step is an unprecedented catalytic enantioselective isomerization of β,γ-unsaturated cyclohex-3-en-1-ones to the corresponding α,β-unsaturated chiral enones. This new asymmetric transformation was realized by cooperative iminium-base catalysis with an electronically tunable new organic catalyst. The synthetic utility of this methodology is highlighted by the enantioselective total synthesis of (−)-isoacanthodoral.

Asymmetric Olefin Isomerization of Butenolides via Proton Transfer Catalysis by an Organic Molecule

Co-reporter:Yongwei Wu ; Ravi P. Singh

Journal of the American Chemical Society 2011 Volume 133(Issue 32) pp:12458-12461

Publication Date(Web):July 18, 2011

DOI:10.1021/ja205674x

An unprecedented enantioselective and general olefin isomerization was realized via biomimetic proton transfer catalysis with a new chiral organic catalyst. A broad range of mono- and disubstituted β,γ-unsaturated butenolides were transformed into the corresponding chiral α,β-unsaturated butenolides in high enantioselectivity and yield in the presence of as low as 0.5 mol % catalyst. Mechanistic studies have revealed the protonation as the rate-determining step.

Highly enantioselective asymmetric Darzens reactions with a phase transfer catalyst

Co-reporter:Yan Liu, Brian A. Provencher, Keith J. Bartelson and Li Deng

Chemical Science 2011 vol. 2(Issue 7) pp:1301-1304

Publication Date(Web):21 Apr 2011

DOI:10.1039/C1SC00137J

A class of easily accessible and readily tunable chiral phase transfer catalysts based on 6′-OH cinchonium salts was found to efficiently catalyze an unprecedented highly enantioselective Darzens reaction of α-chloro ketones and aldehydes, which directly produces optically active chiral epoxides from readily available carbonyl compounds.

Catalytic asymmetric [4 + 2] additions with aliphatic nitroalkenes

Co-reporter:Keith J. Bartelson, Ravi P. Singh, Bruce M. Foxman and Li Deng

Chemical Science 2011 vol. 2(Issue 10) pp:1940-1944

Publication Date(Web):18 Jul 2011

DOI:10.1039/C1SC00326G

We describe an unprecedented cycloaddition reaction of 2-pyrones with aliphatic nitroalkenes catalyzed by a new bifunctional cinchona alkaloid-derived catalyst bearing a bulky TIPS-ether at the 9-position. The [2.2.2] bicyclic adducts were obtained in good yield with excellent diastereo- and enantioselectivity. Carbon isotope effects were measured by 13C NMR and are indicative of a stepwise mechanism. Finally, a synthetic application is demonstrated, highlighting the utility of the cycloadducts.

Cinchona Alkaloid-Catalyzed Enantioselective Amination of ,-Unsaturated Ketones: An Asymmetric Approach to 2-Pyrazolines

Co-reporter:Nathaniel R. Campbell;Bingfeng Sun;Ravi P. Singh

Advanced Synthesis & Catalysis 2011 Volume 353( Issue 17) pp:3123-3128

Publication Date(Web):

DOI:10.1002/adsc.201100447

Abstract

Δ²-Pyrazolines are of significant medicinal and synthetic interest due to their therapeutic properties and utility in the synthesis of 1,3-diamines, yet few asymmetric methods exist to prepare them. An unprecedented and highly enantioselective organocatalytic synthesis of 2-pyrazolines was achieved through an asymmetric conjugate addition catalyzed by 9-epi-amino Cinchona alkaloids followed by deprotection-cyclization, which furnished chiral 2-pyrazolines in 46–78% yield and 59–91% ee. This bifunctional catalytic methodology thus provides easy access to a considerable range of optically active 3,5-dialkyl 2-pyrazolines.

Structural Study-Guided Development of Versatile Phase-Transfer Catalysts for Asymmetric Conjugate Additions of Cyanide

Co-reporter:Brian A. Provencher;Keith J. Bartelson;Dr. Yan Liu; Bruce M. Foxman; Li Deng

Angewandte Chemie 2011 Volume 123( Issue 45) pp:10753-10757

Publication Date(Web):

DOI:10.1002/ange.201105536

Structural Study-Guided Development of Versatile Phase-Transfer Catalysts for Asymmetric Conjugate Additions of Cyanide

Co-reporter:Brian A. Provencher;Keith J. Bartelson;Dr. Yan Liu; Bruce M. Foxman; Li Deng

Angewandte Chemie International Edition 2011 Volume 50( Issue 45) pp:10565-10569

Publication Date(Web):

DOI:10.1002/anie.201105536

Asymmetric Vinylogous Aldol Reaction of Silyloxy Furans with a Chiral Organic Salt

Co-reporter:Ravi P. Singh ; Bruce M. Foxman

Journal of the American Chemical Society 2010 Volume 132(Issue 28) pp:9558-9560

Publication Date(Web):June 29, 2010

DOI:10.1021/ja103331t

Despite their synthetic significance there is a general lack of asymmetric vinylogous aldol reactions that tolerate variations of both the silyloxy furans and aldehydes. We have developed a new chiral organic catalyst based on a carboxylate-ammonium salt prepared from a thiourea-amine and a carboxylic acid. This new catalyst enabled us to develop an efficient asymmetric vinylogous aldol reaction of unprecedented scope with respect to both 2-trimethylsilyloxy furans and aldehydes.

Elucidation of the active conformation of cinchona alkaloid catalyst and chemical mechanism of alcoholysis of meso anhydrides

Co-reporter:Hongming Li;Xiaofeng Liu;Fanghui Wu;Liang Tang

PNAS 2010 Volume 107 (Issue 48 ) pp:20625-20629

Publication Date(Web):2010-11-30

DOI:10.1073/pnas.1004439107

Complementary to enantioselective transformations of planar functionalities, catalytic desymmetrization of meso compounds is another fundamentally important strategy for asymmetric synthesis. However, experimentally established stereochemical models on how a chiral catalyst discriminates between two enantiotopic functional groups in the desymmetrization of a meso substrate are particularly lacking. This article describes our endeavor to elucidate the chemical mechanism and characterization of the active conformation of the cinchona alkaloid-derived catalyst for a desymmetrization of meso cyclic anhydrides via asymmetric alcoholysis. First, our kinetic studies indicate that the cinchona alkaloid-catalyzed alcoholysis proceeds by a general base catalysis mechanism. Furthermore, the active conformer of the cinchona alkaloid-derived catalyst DHQD-PHN was clarified by catalyst conformation studies with a designed, rigid cinchona alkaloid derivative as a probe. These key mechanistic insights enabled us to construct a stereochemical model to rationalize how DHQD-PHN differentiates the two enantiotopic carbonyl groups in the transition state of the asymmetric alcoholysis of meso cyclic anhydrides. This model not only is consistent with the sense of asymmetric induction of the asymmetric alcoholysis but also provides a rationale on how the catalyst tolerates a broad range of cyclic anhydrides. These mechanistic insights further guided us to develop a novel practical catalyst for the enantioselective alcoholysis of meso cyclic anhydrides.

Asymmetric synthesis of β,γ-unsaturated α-amino acids via efficient kinetic resolution with cinchona alkaloids

Co-reporter:Jianfeng Hang, Li Deng

Bioorganic & Medicinal Chemistry Letters 2009 Volume 19(Issue 14) pp:3856-3858

Publication Date(Web):15 July 2009

DOI:10.1016/j.bmcl.2009.03.152

The β,γ-unsaturated amino acids are versatile chiral building blocks and biologically interesting compounds. The asymmetric synthesis of β,γ-unsaturated amino acids presents a challenging task as these compounds are labile toward racemization as well as the undesirable double bond isomerization. An efficient, general and mild kinetic resolution with readily accessible and fully recyclable cinchona alkaloid catalysts has been developed to provide a reliably useful approach toward optically active β,γ-unsaturated amino acids.

Catalytic enantioselective conjugate additions with α,β-unsaturated sulfones

Co-reporter:Hongming Li, Jun Song, Li Deng

Tetrahedron 2009 65(16) pp: 3139-3148

Publication Date(Web):

DOI:10.1016/j.tet.2008.11.054

Asymmetric Aza-Michael Reactions of ,-Unsaturated Ketones with Bifunctional Organic Catalysts

Co-reporter:Xiaojie Lu

Angewandte Chemie International Edition 2008 Volume 47( Issue 40) pp:7710-7713

Publication Date(Web):

DOI:10.1002/anie.200802785

Asymmetric Aza-Michael Reactions of ,-Unsaturated Ketones with Bifunctional Organic Catalysts

Co-reporter:Xiaojie Lu

Angewandte Chemie 2008 Volume 120( Issue 40) pp:7824-7827

Publication Date(Web):

DOI:10.1002/ange.200802785

Construction of Quaternary Stereocenters by Efficient and Practical Conjugate Additions to ,-Unsaturated Ketones with a Chiral Organic Catalyst

Co-reporter:Fanghui Wu, Hongming Li, Ran Hong,Li Deng

Angewandte Chemie International Edition 2006 45(10) pp:1498

Publication Date(Web):

DOI:10.1002/anie.200690034

Construction of Quaternary Stereocenters by Efficient and Practical Conjugate Additions to ,-Unsaturated Ketones with a Chiral Organic Catalyst

Co-reporter:Fanghui Wu, Hongming Li, Ran Hong,Li Deng

Angewandte Chemie International Edition 2006 45(6) pp:947-950

Publication Date(Web):

DOI:10.1002/anie.200502658

Construction of Quaternary Stereocenters by Efficient and Practical Conjugate Additions to α,β-Unsaturated Ketones with a Chiral Organic Catalyst

Co-reporter:Fanghui Wu;Hongming Li;Ran Hong Dr.

Angewandte Chemie 2006 Volume 118(Issue 6) pp:

Publication Date(Web):30 DEC 2005

DOI:10.1002/ange.200502658

Mehrwert: Die konjugierte Addition cyclischer oder acyclischer α-substituierter β-Ketoester an α,β-ungesättigte Ketone mithilfe eines chiralen organischen Katalysators (1) gelingt mit guter Enantioselektivität, Diastereoselektivität und Ausbeute. Diese Strategie zur asymmetrischen C-C-Bindungsbildung liefert eine Vielzahl chiraler Bausteine 2 mit quartären Allkohlenstoffstereozentren.

Construction of Quaternary Stereocenters by Efficient and Practical Conjugate Additions to α,β-Unsaturated Ketones with a Chiral Organic Catalyst

Co-reporter:Fanghui Wu;Hongming Li;Ran Hong Dr.

Angewandte Chemie 2006 Volume 118(Issue 10) pp:

Publication Date(Web):21 FEB 2006

DOI:10.1002/ange.200690034

Asymmetric Synthesis of Chiral Aldehydes by Conjugate Additions with Bifunctional Organocatalysis by Cinchona Alkaloids

Co-reporter:Fanghui Wu;Ran Hong Dr.;Jihan Khan;Xiaofeng Liu

Angewandte Chemie International Edition 2006 Volume 45(Issue 26) pp:

Publication Date(Web):31 MAY 2006

DOI:10.1002/anie.200600867

A highly efficient asymmetric conjugate addition of carbonyl donors to α,β-unsaturated aldehydes is realized with 6′-OH cinchona alkaloids as bifunctional organocatalysts. A wide range of α-substituted β-ketoesters and α-substituted α-cyanoacetates can be employed as donors, whereas acrolein and β-substituted α,β-unsaturated aldehydes are suitable acceptors for this enantioselective addition.

Stereocontrolled Creation of Adjacent Quaternary and Tertiary Stereocenters by a Catalytic Conjugate Addition

Co-reporter:Hongming Li;Yi Wang Dr.;Liang Tang;Fanghui Wu;Xiaofeng Liu;Chengyun Guo;Bruce M. Foxman

Angewandte Chemie International Edition 2005 Volume 44(Issue 1) pp:

Publication Date(Web):26 NOV 2004

DOI:10.1002/anie.200461923

Not too close for comfort: Practical chiral organocatalysts like that shown promote Michael addition reactions of a wide range of trisubstituted carbon nucleophiles to various nitroalkenes, often with nearly perfect stereoselectivity (>99 % ee and >98:2 d.r.). In one step adjacent carbon- or heteroatom-substituted quaternary and tertiary stereocenters are generated from readily available starting materials.

Catalytic Enantioselective Total Syntheses of Bisorbicillinolide, Bisorbicillinol, and Bisorbibutenolide

Co-reporter:Ran Hong Dr.;Yonggang Chen

Angewandte Chemie International Edition 2005 Volume 44(Issue 22) pp:

Publication Date(Web):28 APR 2005

DOI:10.1002/anie.200500480

A modified cinchona alkaloid catalyzed ketone cyanosilylation reaction is used as the stereochemistry-defining step in the total synthesis of sorbicillinol derivatives (a protected derivative is shown (PMB=para-methoxybenzyl)). These enantioselective total syntheses were accomplished in 10/11 steps and 12–19 % overall yields. Furthermore, the chemical conversion of bisorbicillinol into bisorbicillinolide provides insight into the biosynthesis of bisorbicillinolide.

Catalytic Enantioselective Total Syntheses of Bisorbicillinolide, Bisorbicillinol, and Bisorbibutenolide

Co-reporter:Ran Hong Dr.;Yonggang Chen

Angewandte Chemie 2005 Volume 117(Issue 22) pp:

Publication Date(Web):28 APR 2005

DOI:10.1002/ange.200500480

Der konfigurationsbestimmende Schritt in der Totalsynthese von Sorbicillinol-Derivaten (ein geschütztes Derivat ist gezeigt (PMB=para-Methoxybenzyl)) ist eine durch ein modifiziertes China-Alkaloid katalysierte Ketoncyanosilylierung. Diese enantioselektiven Totalsynthesen gelangen in 10/11 Stufen und 12–19 % Gesamtausbeuten. Darüber hinaus verschaffte die chemische Umwandlung von Bisorbicillinol in Bisorbicillinolid einen Einblick in die Biosynthese von Bisorbicillinolid.

Stereocontrolled Creation of Adjacent Quaternary and Tertiary Stereocenters by a Catalytic Conjugate Addition

Co-reporter:Hongming Li;Yi Wang Dr.;Liang Tang;Fanghui Wu;Xiaofeng Liu;Chengyun Guo;Bruce M. Foxman

Angewandte Chemie 2005 Volume 117(Issue 1) pp:

Publication Date(Web):26 NOV 2004

DOI:10.1002/ange.200461923

Chirale Organokatalysatoren wie der gezeigte katalysieren Michael-Additionen einer Vielzahl von trisubstituierten Kohlenstoffnucleophilen an Nitroalkene, häufig mit fast perfekter Stereoselektivität (>99 % ee und >98:2 d.r.). In einem Schritt werden benachbarte quartäre und tertiäre Stereozentren mit nur Kohlenstoff- oder auch Heteroatomsubstituenten aus einfach zugänglichen Ausgangsverbindungen erhalten.

A Highly Enantioselective and General Conjugate Addition of Thiols to Cyclic Enones with an Organic Catalyst

Co-reporter:Paul McDaid;Yonggang Chen Dr.

Angewandte Chemie International Edition 2002 Volume 41(Issue 2) pp:

Publication Date(Web):18 JAN 2002

DOI:10.1002/1521-3773(20020118)41:2<338::AID-ANIE338>3.0.CO;2-M

The mechanism is not yet known but the modified biscinchona alkaloid shown here is an excellent catalyst for the general and highly enantioselective 1,4-addition of thiols to cyclic enones. Selectivities ranging from 93 to >99 % ee were achieved for the addition of 2-thionaphthol to six- to nine-membered enones.

A Highly Enantioselective and General Conjugate Addition of Thiols to Cyclic Enones with an Organic Catalyst

Co-reporter:Paul McDaid;Yonggang Chen Dr.

Angewandte Chemie 2002 Volume 114(Issue 2) pp:

Publication Date(Web):17 JAN 2002

DOI:10.1002/1521-3757(20020118)114:2<348::AID-ANGE348>3.0.CO;2-6

Den Mechanismus kennt man noch nicht, aber jedenfalls katalysiert das gezeigte modifizierte Biscinchona-Alkaloid die hochenantioselektive 1,4-Addition von Thiolen an cyclische Enone ausgezeichnet. Selektivitäten zwischen 93 und >99 % ee wurden bei der Addition von 2-Thionaphthol an sechs- bis neungliedrige Enone erzielt.

Catalytic asymmetric direct aldol reaction of α-alkyl azlactones and aliphatic aldehydes

Co-reporter:Yang Zheng and Li Deng

Chemical Science (2010-Present) 2015 - vol. 6(Issue 11) pp:NaN6514-6514

Publication Date(Web):2015/08/04

DOI:10.1039/C5SC02116B

Highly enantioselective asymmetric Darzens reactions with a phase transfer catalyst

Co-reporter:Yan Liu, Brian A. Provencher, Keith J. Bartelson and Li Deng

Chemical Science (2010-Present) 2011 - vol. 2(Issue 7) pp:NaN1304-1304

Publication Date(Web):2011/04/21

DOI:10.1039/C1SC00137J

Catalytic asymmetric [4 + 2] additions with aliphatic nitroalkenes

Co-reporter:Keith J. Bartelson, Ravi P. Singh, Bruce M. Foxman and Li Deng