A5041041100- Synthetic Organic Chemistry Methods
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
- Catalytic Cross-Coupling Reactions
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Catalytic C–H Functionalization Methods
- Asymmetric Synthesis and Catalysis
- Asymmetric Hydrogenation and Catalysis
- Chemical Synthesis and Analysis
- Radical Photochemical Reactions
- Cyclopropane Reaction Mechanisms
- Sulfur-Based Synthesis Techniques
- Crystallography and molecular interactions
- Chemical Synthesis and Reactions
- Advanced Synthetic Organic Chemistry
- Organoboron and organosilicon chemistry
- Chemical synthesis and alkaloids
- Microbial Natural Products and Biosynthesis
- Synthesis and Catalytic Reactions
- Carbon dioxide utilization in catalysis
- Oxidative Organic Chemistry Reactions
- Synthesis of Indole Derivatives
- Coordination Chemistry and Organometallics
- Metal-Organic Frameworks: Synthesis and Applications
- Axial and Atropisomeric Chirality Synthesis
Northwestern University
2016-2025
Midwestern University
2010-2024
Northwestern University
2023
Northwest University
2007-2016
IPM Institute of North America
2014-2016
Center for Discovery
2014
International Institute for Nanotechnology
2007-2012
Robert H. Lurie Comprehensive Cancer Center of Northwestern University
2010
Truman State University
2009
University of Minnesota
2009
A scalable, reproducible method of synthesizing UiO-66- and UiO-67-type MOFs, entailing the addition HCl to reaction mixture, has been investigated. The new protocol requires a fraction time previously reported procedures, yields exceptional porosities, works with range linkers.
The existence of single-molecule surface-enhanced Raman spectroscopy (SMSERS) is proven by employing a frequency-domain approach. This demonstrated using two isotopologues Rhodamine 6G that offer unique vibrational signatures. When an average one molecule was adsorbed per silver nanoparticle, only isotopologue typically observed under dry N2 environment. Additionally, the distribution frequencies hidden ensemble revealed examining spectra. Correlation with transmission electron microscopy...
Abstract Das 3,3′‐Pyrrolidinylspirooxindol‐System ist ein privilegiertes heterocyclisches Strukturmotiv, das die zentrale Einheit bei einer großen Familie von natürlichen Alkaloiden mit starken Bioaktivitätsprofilen und interessanten Struktureigenschaften bildet. Neue bedeutende Fortschritte der Synthese dieses kondensierten heterocyclischen Systems haben starkes Interesse an Entwicklung verwandter Verbindungen als mögliche Wirkstoffe oder biologische Sonden hervorgerufen.
Lewis acid activation with N-heterocyclic carbene (NHC) catalysis has presented new opportunities for enantioselective reaction development. Recent findings illustrate that acids can play an important role in homoenolate annulations by: enhancement of the reactivity, reversal diastereo- or regioselectivity, and previously inactive electrophiles. Additionally, incorporation a into Brønsted base-catalyzed conjugate addition allowed increase yields.
Single-molecule surface-enhanced Raman spectroscopy (SMSERS) of crystal violet (CV) has been reported since 1997, yet others have offered alternative explanations that do not necessarily imply SMSERS. Recently, the isotopologue approach, a statistically significant method to establish SMSERS, implemented for members rhodamine dye family. We provide first demonstration SMSERS triphenylmethane using approach. Two isotopologues CV are employed create chemically identical vibrationally distinct...
N-Heterocyclic carbenes derived from benzimidazolium salts are effective catalysts for generating homoenolate species alpha,beta-unsaturated aldehydes. These nucleophilic intermediates can be protonated, and the resulting activated carbonyl unit is trapped with an alcohol nucleophile, thereby promoting a highly efficient conversion of aldehyde into saturated ester. A kinetic resolution secondary alcohols achieved using chiral imidazoylidene catalysts. [reaction: see text]
A dual activation strategy integrating N-heterocyclic carbene (NHC) catalysis and a second Lewis base has been developed. NHC-bound homoenolate equivalents derived from α,β-unsaturated aldehydes combine with transient reactive o-quinone methides in an enantioselective formal [4 + 3] fashion to access 2-benzoxopinones. The overall approach provides general blueprint for the integration of additional modes.
A new approach that takes advantage of N-heterocyclic carbene/Lewis acid cooperative catalysis provides access to cis-1,3,4-trisubstituted cyclopentenes from enals and chalcone derivatives with high levels diastereoselectivity enantioselectivity. The presence Ti(OiPr)4 as the Lewis allows for efficient substrate preorganization, which translates into diastereoselectivity. Additionally, we demonstrate possibility controlling absolute stereochemistry NHC-catalyzed reactions by employing a...
A new urea-containing metal-organic framework (MOF) was synthesized to act as a heterogeneous catalyst. Ureas are well-known for self-recognition and aggregation behavior, resulting in loss of catalytic competency. The catalyst spatial isolation achievable porous MOF environment suggests potentially general solution. combination symmetrical urea tetracarboxylate strut, 4,4'-bipyridine, Zn(NO(3))(2)·6H(2)O under solvothermal conditions afforded microporous (NU-601). This material is indeed an...
N-Heterocyclic carbenes derived from N-mesityl benzimidazolium salts are effective catalysts for generating homoenolate species α,β-unsaturated aldehydes. The nucleophilic intermediate adds to azomethine imines, and the resulting activated carbonyl unit undergoes an intramolecular acylation event. This formal [3 + 3] cycloaddition between aldehydes imines catalyzed by NHC has been developed give substituted pyridazinones in good excellent yields with high diastereoselectivity (>20:1)....
A cooperative catalysis approach for the enantioselective formal [3+2] addition of α,β-unsaturated aldehydes to isatins has been developed. Homoenolate annulations β-aryl enals catalyzed by an N-heterocyclic carbene (NHC) require lithium chloride high levels enantioselectivity. This NHC-catalyzed annulation used total synthesis maremycin B.
ortho-Quinone methides have emerged recently as useful electrophiles in metal-free catalysis. New strategies to access these species situ that are compatible with simultaneous nucleophile generation provided a suite of innovative and selective transformations accessing heterocycles for use organic synthesis.
An existence proof for single-molecule tip-enhanced Raman spectroscopy (SMTERS) is given using the frequency domain approach involving two isotopologues of Rhodamine 6G (R6G) that were previously employed surface-enhanced (SMSERS). A combination experimental and theoretical studies provides a detailed view isotopic response R6G–d0 R6G–d4 in 600 – 800 cm–1 region. The nature TERS experiment confirmed through lines evidence. First, vibrational signature only one isotopologue at time was...
A convergent, catalytic asymmetric formal [4 + 2] annulation for the synthesis of dihydroquinolones has been developed. Carboxylic acids can be employed as precursors to NHC enolates through an in situ activation strategy. Simultaneous generation a reactive aza-o-quinone methide under basic conditions leads dual approach.
Training algorithms to computationally plan multistep organic syntheses has been a challenge for more than 50 years1-7. However, the field progressed greatly since development of early programs such as LHASA1,7, which reaction choices at each step were made by human operators. Multiple software platforms6,8-14 are now capable completely autonomous planning. But these 'think' only one time and have so far limited relatively simple targets, could arguably be designed chemists within minutes,...
Abstract As a key element in the construction of complex organic scaffolds, formation C−C bonds remains challenge field synthetic chemistry. Recent advancements single‐electron chemistry have enabled new methods for various bonds. Disclosed herein is development novel reduction acyl azoliums ketones from carboxylic acids. Facile azolium situ followed by radical–radical coupling was made possible merging N‐heterocyclic carbene (NHC) and photoredox catalysis. The utility this protocol...
Photoinduced hydrogen atom transfer (HAT) has been developed as a powerful tool to generate synthetically valuable radical species. The direct photoexcitation of ketones known promote HAT or acyl radicals through Norrish-type pathways, but these modalities remain severely limited by side reactions. We report herein catalyst- and transition metal-free method for the acylation C-H bonds that leverages unique properties stable, isolable azolium Specifically, salts are shown undergo an...