1
|
Kamata K, Kuriyama M, Tahara H, Nishikawa A, Yamamoto K, Demizu Y, Onomura O. One-pot C(sp 3)-H difluoroalkylation of tetrahydroisoquinolines and isochromans via electrochemical oxidation and organozinc alkylation. Chem Commun (Camb) 2024. [PMID: 38832582 DOI: 10.1039/d4cc02033b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
The C(sp3)-H difluoroalkylation for the introduction of carbonylated CF2 groups into tetrahydroisoquinolines (THIQs) and isochromans has been achieved by using electrochemical oxidation and organozinc alkylation. This one-pot process proceeded smoothly under transition-metal catalyst- and chemical oxidant-free conditions, and the desired products were obtained in good to high yields with a broad scope, except for N-Boc-THIQ. In addition, the gram-scale experiment successfully demonstrated the promising scalability. This is the first example of an electrochemical method for C(sp3)-H difluoroalkylation of amines and ethers.
Collapse
Affiliation(s)
- Kazuya Kamata
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
| | - Masami Kuriyama
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
| | - Hironobu Tahara
- Graduate School of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Akira Nishikawa
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
| | - Kosuke Yamamoto
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
| | - Yosuke Demizu
- Division of Organic Chemistry, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki, Kanagawa 210-9501, Japan
| | - Osamu Onomura
- Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
| |
Collapse
|
2
|
Pan QJ, Miao YQ, Cao HJ, Liu Z, Chen X. Visible Light-Induced 1,2-Diphenyldisulfane-Mediated Defluoroborylation of Polyfluoroarenes. J Org Chem 2024; 89:5049-5059. [PMID: 38491018 DOI: 10.1021/acs.joc.4c00286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2024]
Abstract
A green and practical protocol of defluoroborylation of polyfluoroarenes with stable and readily accessible NHC-borane was developed, using 1,2-diphenyldisulfane as a hydrogen atom transfer (HAT) and single electron transfer (SET) reagent precursor under visible-light irradiation, leading to the concise formation of value-added fluorinated organoboron scaffolds. Mechanism studies revealed the method underwent a boryl radical addition reaction with polyfluoroarene, followed by successive single electron transfer pathways and defluorination of the C-F bond to offer the targeted product. This unprecedented platform relies on 1,2-diphenyldisulfane and base without using expensive photocatalysts, highlighting the methodology has promising application value to prepare borylated polyfluoroarene compounds.
Collapse
Affiliation(s)
- Qiao-Jing Pan
- Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Yu-Qi Miao
- Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Hou-Ji Cao
- Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
| | - Zhenxing Liu
- College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Xuenian Chen
- Henan Key Laboratory of Boron Chemistry and Advanced Energy Materials, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China
- College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China
| |
Collapse
|
3
|
Guan YQ, Qiao JF, Liang YF. Nickel-catalysed chelation-assisted reductive defluorinative sulfenylation of trifluoropropionic acid derivatives. Chem Commun (Camb) 2024; 60:2405-2408. [PMID: 38323634 DOI: 10.1039/d3cc06041a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Herein we reported a directing-group assisted strategy for nickel-catalysed reductive defluorinative sulfenylation of trifluoropropionic acid derivatives with disulfides in the presence of Zn, involving triple C-F bond cleavage. This process yielded a diverse array of carbonyl-sulfide di-substituted alkenes in moderate to good yields with good functional group tolerance. Specifically, the reactions exhibited high E-selectivity with E/Z ratio up to >99 : 1.
Collapse
Affiliation(s)
- Yu-Qiu Guan
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.
| | - Jia-Fan Qiao
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.
| | - Yu-Feng Liang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.
| |
Collapse
|
4
|
Zhu XL, Wang H, Zhai CK, He W. Photo-induced C(sp 2)-H difluoroalkylation of anilines. Org Biomol Chem 2024; 22:720-724. [PMID: 38165818 DOI: 10.1039/d3ob01757e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
A photoinduced protocol for the direct difluoroalkylation of C(sp2)-H bonds in anilines under catalyst-free reaction conditions is presented. This transformation is characterized by a wide substrate scope, mild reaction conditions, and operational simplicity, and could serve as an alternative tool to established methods for the synthesis of difluoroalkylated anilines. Mechanistic studies suggest the formation of an electron-donor-acceptor (EDA) complex between anilines and difluoroalkyl bromides in this reaction.
Collapse
Affiliation(s)
- Xing-Li Zhu
- Department of Chemistry, School of Pharmacy, Air Force Medical University, Xi'an 710032, P.R.China.
| | - Hua Wang
- Department of Chemistry, School of Pharmacy, Air Force Medical University, Xi'an 710032, P.R.China.
| | - Chen-Kai Zhai
- Department of Chemistry, School of Pharmacy, Air Force Medical University, Xi'an 710032, P.R.China.
| | - Wei He
- Department of Chemistry, School of Pharmacy, Air Force Medical University, Xi'an 710032, P.R.China.
| |
Collapse
|
5
|
Majhi J, Molander GA. Recent Discovery, Development, and Synthetic Applications of Formic Acid Salts in Photochemistry. Angew Chem Int Ed Engl 2024; 63:e202311853. [PMID: 37812639 DOI: 10.1002/anie.202311853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/05/2023] [Accepted: 10/09/2023] [Indexed: 10/11/2023]
Abstract
The advancement of sustainable photoredox catalysis in synthetic organic chemistry has evolved immensely because of the development of versatile and cost-effective reagents. In recent years, a substantial effort has been dedicated to exploring the utility of formic acid salts in various photochemical reactions. In this context, formates have demonstrated diverse capabilities, functioning as reductants, sources of carbonyl groups, and reagents for hydrogen atom transfer. Notably, the CO2 ⋅- radical anion derived from formate exhibits strong reductant properties for cleaving both C-X and C-O bonds. Moreover, these salts play a pivotal role in carboxylation reactions, further highlighting their significance in a variety of photochemical transformations. The ability of formates to serve as reductants, carbonyl sources, and hydrogen atom transfer reagents reveal exciting possibilities in synthetic organic chemistry. This minireview highlights an array of captivating discoveries, underscoring the crucial role of formates in diverse and distinctive photochemical methods, enabling access to a wide range of value-added compounds.
Collapse
Affiliation(s)
- Jadab Majhi
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Gary A Molander
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| |
Collapse
|
6
|
Chen M, Cui Y, Chen X, Shang R, Zhang X. C-F bond activation enables synthesis of aryl difluoromethyl bicyclopentanes as benzophenone-type bioisosteres. Nat Commun 2024; 15:419. [PMID: 38199996 PMCID: PMC10781780 DOI: 10.1038/s41467-023-44653-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 12/22/2023] [Indexed: 01/12/2024] Open
Abstract
Bioisosteric design has become an essential approach in the development of drug molecules. Recent advancements in synthetic methodologies have enabled the rapid adoption of this strategy into drug discovery programs. Consequently, conceptionally innovative practices would be appreciated by the medicinal chemistry community. Here we report an expeditous synthetic method for synthesizing aryl difluoromethyl bicyclopentane (ADB) as a bioisostere of the benzophenone core. This approach involves the merger of light-driven C-F bond activation and strain-release chemistry under the catalysis of a newly designed N-anionic-based organic photocatalyst. This defluorinative coupling methodology enables the direct conversion of a wide variety of commercially available trifluoromethylaromatic C-F bonds (more than 70 examples) into the corresponding difluoromethyl bicyclo[1.1.1]pentanes (BCP) arenes/difluoromethyl BCP boronates in a single step. The strategy can also be applied to [3.1.1]and [4.1.1]propellane systems, providing access to analogues with different geometries. Moreover, we have successfully used this protocol to rapidly prepare ADB-substituted analogues of the bioactive molecule Adiporon. Biological testing has shown that the ADB scaffold has the potential to enhance the pharmacological properties of benzophenone-type drug candidates.
Collapse
Affiliation(s)
- Mingshuo Chen
- School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, 310024, Hangzhou, People's Republic of China
| | - Yuang Cui
- School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, 310024, Hangzhou, People's Republic of China
| | - Xiaoping Chen
- School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, 310024, Hangzhou, People's Republic of China
| | - Rui Shang
- Department of Chemistry, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Xiaheng Zhang
- School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, 310024, Hangzhou, People's Republic of China.
| |
Collapse
|
7
|
Fan Y, Huang Z, Lu Y, Zhu S, Chu L. Defluorinative Alkylboration of Alkenes Enabled by Dual Photoredox and Copper Catalysis. Angew Chem Int Ed Engl 2023:e202315974. [PMID: 38065842 DOI: 10.1002/anie.202315974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Indexed: 12/22/2023]
Abstract
A regioselectivity reversed three-component defluorinative alkylboration of alkenes with trifluoromethyls and bis(pinacolato)diboron via dual photoredox/copper catalysis is reported. The mild conditions are compatible with a wide array of nonactivated trifluoromethyl aromatics bearing electron-donating or electron-neutral substituents, trifluoroacetamides, and various nonactivated terminal and internal alkenes, enabling straightforward access to synthetically valuable γ-gem-difluoroalkyl boronates with high efficiency. Furthermore, this protocol is applicable to alkene-tethered trifluoromethyl aromatics to furnish gem-difluoromethylene-containing cyclic compounds. Synthetic applications and preliminary mechanistic studies are also presented.
Collapse
Affiliation(s)
- Yanmin Fan
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering, Center for Advanced Low-Dimension Materials, Donghua University, Shanghai, 201620, China
| | - Zhonghou Huang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering, Center for Advanced Low-Dimension Materials, Donghua University, Shanghai, 201620, China
| | - Yi Lu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering, Center for Advanced Low-Dimension Materials, Donghua University, Shanghai, 201620, China
| | - Shengqing Zhu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering, Center for Advanced Low-Dimension Materials, Donghua University, Shanghai, 201620, China
| | - Lingling Chu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering, Center for Advanced Low-Dimension Materials, Donghua University, Shanghai, 201620, China
| |
Collapse
|
8
|
Hooker LV, Bandar JS. Synthetic Advantages of Defluorinative C-F Bond Functionalization. Angew Chem Int Ed Engl 2023; 62:e202308880. [PMID: 37607025 PMCID: PMC10843719 DOI: 10.1002/anie.202308880] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/20/2023] [Accepted: 08/21/2023] [Indexed: 08/24/2023]
Abstract
Much progress has been made in the development of methods to both create compounds that contain C-F bonds and to functionalize C-F bonds. As such, C-F bonds are becoming common and versatile synthetic functional handles. This review summarizes the advantages of defluorinative functionalization reactions for small molecule synthesis. The coverage is organized by the type of carbon framework the fluorine is attached to for mono- and polyfluorinated motifs. The main challenges, opportunities and advances of defluorinative functionalization are discussed for each class of organofluorine. Most of the text focuses on case studies that illustrate how defluorofunctionalization can improve routes to synthetic targets or how the properties of C-F bonds enable unique mechanisms and reactions. The broader goal is to showcase the opportunities for incorporating and exploiting C-F bonds in the design of synthetic routes, improvement of specific reactions and advent of new methods.
Collapse
Affiliation(s)
- Leidy V Hooker
- Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA
| | - Jeffrey S Bandar
- Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA
| |
Collapse
|
9
|
Yue WJ, Martin R. α-Difluoroalkylation of Benzyl Amines with Trifluoromethylarenes. Angew Chem Int Ed Engl 2023; 62:e202310304. [PMID: 37596243 DOI: 10.1002/anie.202310304] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 08/20/2023]
Abstract
An α-difluoroalkylation of benzyl amines with trifluoromethylarenes is disclosed herein. This protocol is characterized by its operational simplicity, excellent chemoselectivity and broad scope-even with advanced synthetic intermediates-, thus offering a new entry point to medicinally-relevant α-difluoroalkylated amines from simple, yet readily accessible, precursors.
Collapse
Affiliation(s)
- Wen-Jun Yue
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain
- Universitat Rovira i Virgili, Departament de Química Analítica i Química Orgànica, c/Marcel⋅lí Domingo, 1, 43007, Tarragona, Spain
| | - Ruben Martin
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology, Av. Països Catalans 16, 43007, Tarragona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluïs Companys, 23, 08010, Barcelona, Spain
| |
Collapse
|
10
|
Gallego-Gamo A, Granados A, Pleixats R, Gimbert-Suriñach C, Vallribera A. Difluoroalkylation of Anilines via Photoinduced Methods. J Org Chem 2023; 88:12585-12596. [PMID: 37585266 PMCID: PMC10476199 DOI: 10.1021/acs.joc.3c01298] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Indexed: 08/18/2023]
Abstract
The development of sustainable and mild protocols for the fluoroalkylation of organic backbones is of current interest in chemical organic synthesis. Herein, we present operationally simple and practical transition-metal-free methods for the preparation of difluoroalkyl anilines. First, a visible-light organophotocatalytic system working via oxidative quenching is described, providing access to a wide range of difluoroalkyl anilines under mild conditions. In addition, the formation of an unprecedented electron donor-acceptor (EDA) complex between anilines and ethyl difluoroiodoacetate is reported and exploited as an alternative, efficient, and straightforward strategy to prepare difluoroalkyl derivatives.
Collapse
Affiliation(s)
- Albert Gallego-Gamo
- Department of Chemistry and
Centro de Innovación en Química Avanzada (ORFEO−CINQA), Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Barcelona, Spain
| | - Albert Granados
- Department of Chemistry and
Centro de Innovación en Química Avanzada (ORFEO−CINQA), Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Barcelona, Spain
| | - Roser Pleixats
- Department of Chemistry and
Centro de Innovación en Química Avanzada (ORFEO−CINQA), Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Barcelona, Spain
| | - Carolina Gimbert-Suriñach
- Department of Chemistry and
Centro de Innovación en Química Avanzada (ORFEO−CINQA), Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Barcelona, Spain
| | - Adelina Vallribera
- Department of Chemistry and
Centro de Innovación en Química Avanzada (ORFEO−CINQA), Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Barcelona, Spain
| |
Collapse
|
11
|
Li R, Yang X, Guan W. Photocatalytic C-F alkylation of trifluoromethyls using o-phosphinophenolate: mechanistic insights and substrate prediction. Chem Commun (Camb) 2023; 59:10648-10651. [PMID: 37581000 DOI: 10.1039/d3cc03264g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
Density functional theory computations reveal the radical mechanism of photocatalytic defluoroalkylation and hydrodefluorination of N-phenyl-2,2,2-trifluoromethylacetamide with o-phosphinophenolate (PO) cooperative catalysis. The energy gaps between the singlet substrate LUMOs and triplet photocatalyst SOMOs can be used as an effective "chemical descriptor" for predicting catalyst activity. Cesium formate assisted C-F bond activation is the most favorable path. A series of available organic structures are computationally predicted as potential substrates.
Collapse
Affiliation(s)
- Rongrong Li
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry Chinese Academy of Sciences, Beijing 100190, P. R. China.
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Xinzheng Yang
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry Chinese Academy of Sciences, Beijing 100190, P. R. China.
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Wei Guan
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China.
| |
Collapse
|
12
|
Shreiber ST, Molander GA. Alkyl (Het)Arylsulfones from SuFEx Reagents via Photochemical S-F Bond Activation. Org Lett 2023; 25:2084-2087. [PMID: 36939137 DOI: 10.1021/acs.orglett.3c00447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2023]
Abstract
A visible light-induced S-F bond activation of sulfur fluoride exchange (SuFEx) reagents to generate alkyl sulfones is described. The method is free of transition metals and relies on the use of commercially available commodity chemicals. In addition, this method demonstrates the first photoredox functionalization of SuFEx reagents. The reaction has a diverse substrate scope, with applications in various aryl sulfonyl fluorides, both activated and unactivated alkenes.
Collapse
Affiliation(s)
- Scott T Shreiber
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Gary A Molander
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| |
Collapse
|
13
|
Dhungana RK, Granados A, Ciccone V, Martin RT, Majhi J, Sharique M, Gutierrez O, Molander GA. Trifunctionalization of Cinnamyl Alcohols Provides Access to Brominated α,α-Difluoro-γ-lactones via a Photoinduced Radical–Polar–Radical Mechanism. ACS Catal 2022. [DOI: 10.1021/acscatal.2c05514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Roshan K. Dhungana
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Albert Granados
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Vittorio Ciccone
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Robert T. Martin
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Jadab Majhi
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Mohammed Sharique
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Osvaldo Gutierrez
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Gary A. Molander
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| |
Collapse
|