A5037620851- Catalytic C–H Functionalization Methods
- Asymmetric Synthesis and Catalysis
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Catalytic Cross-Coupling Reactions
- Asymmetric Hydrogenation and Catalysis
- Synthetic Organic Chemistry Methods
- Sulfur-Based Synthesis Techniques
- Chemical Synthesis and Analysis
- Synthesis and Catalytic Reactions
- Radical Photochemical Reactions
- Cyclopropane Reaction Mechanisms
- Chemical Synthesis and Reactions
- Crystallography and molecular interactions
- Coordination Chemistry and Organometallics
- Oxidative Organic Chemistry Reactions
- Organometallic Complex Synthesis and Catalysis
- Advanced Synthetic Organic Chemistry
- Organoboron and organosilicon chemistry
- Axial and Atropisomeric Chirality Synthesis
- Molecular spectroscopy and chirality
- Fluorine in Organic Chemistry
- Synthesis of Indole Derivatives
- Atmospheric chemistry and aerosols
- Chemical synthesis and alkaloids
University of Pennsylvania
2016-2025
Center for Global Health
2023
St. Jude Children's Research Hospital
2023
Molecular Oncology (United States)
2023
Georgetown University
2023
Philadelphia University
2011-2021
California University of Pennsylvania
2007-2021
Merck (Singapore)
2014-2021
High Throughput Biology (United States)
2014-2021
University of South Carolina
2018-2021
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStoichiometric and catalytic hydroamination of alkynes allene by zirconium bisamides Cp2Zr(NHR)2Patrick J. Walsh, Anne M. Baranger, Robert G. BergmanCite this: Am. Chem. Soc. 1992, 114, 5, 1708–1719Publication Date (Print):February 1, 1992Publication History Published online1 May 2002Published inissue 1 February 1992https://pubs.acs.org/doi/10.1021/ja00031a026https://doi.org/10.1021/ja00031a026research-articleACS PublicationsRequest reuse...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGeneration, alkyne cycloaddition, arene carbon-hydrogen activation, nitrogen-hydrogen activation and dative ligand trapping reactions of the first monomeric imidozirconocene (Cp2Zr:NR) complexesPatrick J. Walsh, Frederick Hollander, Robert G. BergmanCite this: Am. Chem. Soc. 1988, 110, 26, 8729–8731Publication Date (Print):December 1, 1988Publication History Published online1 May 2002Published inissue 1 December...
A complex role for chlorine radicals Radicals are atoms or molecules that highly reactive because they have an unpaired electron. common means of investigating whether involved in a particular reaction is to try trap them with acceptor compound. Yang et al. reinvestigated photoinduced alkane oxidation which trapping study had previously implicated alkoxy radicals. Their spectroscopic, kinetic, and isotopic labeling studies revealed chlorine, rather than alkoxy, was the key radical...
NHC-Organokatalyse (NHC=N-heterocyclisches Carben) in Gegenwart von Übergangsmetallen ist schwierig, wegen der hohen Affinität NHCs für Metalle. J. Mao, P. Walsh et al. präsentieren ihrer Zuschrift auf S. 167 ein System die konjugierte Addition Aryliodiden an Enale durch kooperative Katalyse zwischen einem NHC- und Pd-Katalysator. Die Katalysezyklen überschneiden sich bei Pd, wo beiden neu gebildeten Pd-C-Bindungen eine reduktive Eliminierung unter Bildung einer C-C-Bindung eingehen.
A unique nickel/organic photoredox co-catalyzed asymmetric reductive cross-coupling between α-chloro esters and aryl iodides is developed. This cross-electrophile coupling reaction employs an organic reductant (Hantzsch ester), whereas most reactions use stoichiometric metals. diverse array of valuable α-aryl formed under these conditions with high enantioselectivities (up to 94 %) good yields 88 %). α-Aryl represent important family nonsteroidal anti-inflammatory drugs. novel synergistic...
A mild photoredox catalyzed construction of sulfides, disulfides, selenides, sulfoxides and sulfones from unstrained ketone precursors is introduced. Combination this deacylative process with S
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMonomeric and dimeric zirconocene imido compounds: synthesis, structure, reactivityPatrick J. Walsh, Frederick Hollander, Robert G. BergmanCite this: Organometallics 1993, 12, 9, 3705–3723Publication Date (Print):September 1, 1993Publication History Published online1 May 2002Published inissue 1 September 1993https://pubs.acs.org/doi/10.1021/om00033a049https://doi.org/10.1021/om00033a049research-articleACS PublicationsRequest reuse...
Although metal-catalyzed direct arylation reactions of non- or weakly acidic C–H bonds have recently received much attention, chemists relied heavily on substrates with appropriately placed directing groups to steer reactivity. To date, examples intermolecular unactivated C(sp3)–H in the absence a group remain scarce. We report herein first general, high-yielding, and scalable method for palladium-catalyzed simple diarylmethane derivatives aryl bromides at room temperature. This facilitates...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTVariable regiochemistry in the stoichiometric and catalytic hydroamination of alkynes by imidozirconium complexes caused an unusual dependence rate law on alkyne structure temperatureAnne M. Baranger, Patrick J. Walsh, Robert G. BergmanCite this: Am. Chem. Soc. 1993, 115, 7, 2753–2763Publication Date (Print):April 1, 1993Publication History Published online1 May 2002Published inissue 1 April...
The asymmetric addition of alkyl groups to aldehydes catalyzed by BINOLate−titanium complexes has become the testing grounds evaluate potential new BINOL-based ligands. We have investigated mechanism this reaction and report our findings here. Model systems for open form catalyst, (BINOLate)[Ti(O-i-Pr)3]2, based on mono-oxygen-alkylated BINOL ligands been examined. Comparison reactivity enantioselectivity mono-alkyl derivatives with those indicate that is not active in reaction. Several...
The first cobalt-catalyzed asymmetric Kumada cross-coupling with high enantioselectivity has been developed. reaction affords a unique strategy for the enantioselective arylation of α-bromo esters catalyzed by cobalt–bisoxazoline complex. A variety chiral α-arylalkanoic were prepared in excellent and yield (up to 97% ee 96% yield). arylated products transformed into α-arylcarboxylic acids primary alcohols without erosion ee. new enantioenriched α-arylpropionic synthesized herein are...
Although the past 15 years have witnessed development of sterically bulky and electron-rich alkylphosphine ligands for palladium-catalyzed cross-couplings with aryl chlorides, examples palladium catalysts based on either triarylphosphine or bidentate phosphine efficient room temperature cross-coupling reactions unactivated chlorides are rare. Herein we report a catalyst NiXantphos, deprotonatable chelating aryldiphosphine ligand, to oxidatively add at temperature. Surprisingly, comparison an...
The reaction of ozone with isoprene, one the most abundant volatile organic compounds in atmosphere, produces three distinct carbonyl oxide species (RR′COO) known as Criegee intermediates: formaldehyde (CH2OO), methyl vinyl ketone (MVK-OO), and methacrolein (MACR-OO). nature substituents (R,R′ = H, CH3, CH═CH2) conformations intermediates control their subsequent chemistry atmosphere. In particular, unimolecular decay MVK-OO is predicted to be major source hydroxyl radicals (OH) isoprene...
The Tsuji–Trost allylic substitution reaction provides a useful and efficient approach to construct C–C bonds between sp3-hybridized carbons. widely accepted paradigm for classifying the mode of attack nucleophiles on palladium π-allyl intermediates in is based pKa pronucleophile: (1) stabilized or "soft" carbon heteroatom (e.g., pronucleophiles with pKa's < 25), (2) unstabilized "hard" (those from > 25). One keys continuing development processes remains broadening scope nucleophiles. Herein...
Light-mediated transformations with CO2 have recently attracted great attention, the focus on incorporation into C-C double and triple bonds, organohalides amines. Herein is demonstrated visible light -mediated umpolung imine reactivity capable of engaging to afford α-amino acid derivatives. By employing benzophenone ketimine derivatives, fixation by hydrocarboxylation C=N bonds achieved. Good excellent yields a broad range α,α-disubstituted derivatives are obtained under mild conditions...
Abstract A novel approach to produce diaryl sulfoxides from aryl benzyl is reported. Optimization of the reaction conditions was performed using high‐throughput experimentation techniques. The [Pd(dba) 2 ]/NiXantPhos catalyst system successfully promotes a triple relay process involving sulfoxide α‐arylation, CS bond cleavage, and formation. byproduct benzophenone formed by an additional palladium‐catalyzed process. It noteworthy that benzylative cleavage unprecedented. wide range...
The palladium-catalyzed α-arylation of unactivated sulfoxides has been developed. weakly acidic α-protons are reversibly deprotonated by LiOtBu, and a palladium phosphine complex facilitates the arylation. A variety aryl methyl were coupled with bromides. More challenging coupling partners, such as alkyl (including dimethyl sulfoxide) chlorides proved to be suitable under optimized conditions. This method was utilized synthesize bioactive benzyl sulfoxide intermediates.
For bioactive molecules, bicyclo[1.1.1]pentanes (BCPs) are an emerging isostere of rigid spacer groups that have shown potential to improve drug-like qualities. As BCPs become increasingly popular motif for evaluation in drug candidates, organic chemists must meet the demand reliably incorporate them into new targets. To provide access BCP analogues diaryl methanamines, a ubiquitous scaffold medicinal chemistry, we report synthesis benzylamines through reactivity [1.1.1]propellane with...
Isoprene has the highest emission into Earth's atmosphere of any nonmethane hydrocarbon. Atmospheric processing alkenes, including isoprene, via ozonolysis leads to formation zwitterionic reactive intermediates, known as Criegee intermediates (CIs). Direct studies have revealed that reactions involving simple CIs can significantly impact tropospheric oxidizing capacity, enhance particulate formation, and degrade local air quality. Methyl vinyl ketone oxide (MVK-oxide) is a four-carbon,...
Abstract Despite remarkable recent advances in transition-metal-catalyzed C(sp 3 )−C cross-coupling reactions, there remain challenging bond formations. One class of such reactions include the formation tertiary -C(sp bonds, presumably due to unfavorable steric interactions and competing isomerizations alkyl metal intermediates. Reported herein is a Ni-catalyzed migratory 3,3-difluoroallylation unactivated bromides at remote centers. This approach enables facile construction otherwise...