Article
Chemistry, Multidisciplinary
Hu Tian, Hong-Ming Zhang, Liang Yin
Summary: In this article, a copper(I)-catalyzed asymmetric conjugate addition/protonation with selenols and alpha-substituted alpha,beta-unsaturated thioamides is described, which produces a series of chiral selenides with high to excellent enantioselectivity. The reaction shows a broad substrate scope for both selenols and alpha-substituted alpha,beta-unsaturated thioamides. The catalytic system is also successfully used for asymmetric selenation of beta-substituted alpha,beta-unsaturated thioamides. A [Cu-(R,R-P)-TANIAPHOS]-SePh species is identified by Se-77 NMR spectra, with a chemical shift at delta 462 ppm. Furthermore, a {[Cu-(R)-TOL-BINAP]-SePh}(2) species is characterized by X-ray analysis, confirming the formation of Cu-Se bond in the reaction. Finally, the straightforward transformations of the thioamide group to amine and thioester are demonstrated.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Ding Yuan, Alister S. Goodfellow, Kevin Kasten, Zhuan Duan, Tengfei Kang, David B. Cordes, Aidan P. Mckay, Michael Buhl, Gregory R. Boyce, Andrew D. Smith
Summary: This study demonstrates the enantioselective conjugate addition of carbo- and heterocyclic alpha-substituted beta-ketoesters to alpha,beta-unsaturated aryl esters using HyperBTM as a catalyst. Divergent diastereoselectivity is observed depending on the substituents of the beta-ketoesters, but both cyclopentanone-derived and indanone-derived beta-ketoesters generate desired products with high selectivity.
Article
Chemistry, Organic
Jinyi Qian, Hengyuan Zhao, Qi Gao, Lirong Chen, Yinrui Shi, Jiuling Li, Yafei Guo, Baomin Fan
Summary: In this research, a new strategy for the asymmetric carbon-phosphorus bond forming reaction using CBS catalysts via non-covalent interactions was disclosed. Various alpha,beta-unsaturated ketones showed remarkable tolerance to various diarylphosphine oxides, and a new application of oxazaborolidines in enantioselective phospha-Michael addition to alpha,beta-unsaturated ketones under mild reaction conditions was developed.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Organic
Jinyi Qian, Hengyuan Zhao, Qi Gao, Lirong Chen, Yinrui Shi, Jiuling Li, Yafei Guo, Baomin Fan
Summary: Classical proline-derived oxazaborolidines, known as CBS catalysts, have significant applications in asymmetric catalysis. This research reveals a new strategy for asymmetric carbon-phosphorus bond formation using CBS catalysts through non-covalent interactions. Various α,β-unsaturated ketones showed excellent tolerance to different diarylphosphine oxides.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Multidisciplinary
Liang Tang, Yicong Luo, Cheng Sheng, Fang Xie, Wanbin Zhang
Summary: This article reports the efficient kinetic resolution of gamma-substituted alpha,beta-unsaturated gamma-lactams via a Cu-catalyzed asymmetric boron conjugate addition, which leads to the synthesis of chiral beta-hydroxy-gamma-lactams with beta,gamma-stereogenic carbon centers. The method is successful with a wide range of substrates and exhibits versatile transformations and synthetic utility in biologically active molecules. Mechanistic studies indicate that a Lewis acid Cu-I-catalyzed mechanism is the likely pathway in the catalytic reaction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Ajay Sharma, Satyendra Kumar Pandey
Summary: A novel and metal-free tandem approach for synthesizing alpha-substituted (E)-alpha,beta-unsaturated aldehyde derivatives has been developed, which involves acid-catalyzed epoxide rearrangement and organocatalyzed aldol condensation processes. This method exhibits a broad substrate scope and mild reaction conditions, resulting in moderate to high yields. Examples of large-scale reactions and the synthesis of bioactive molecules demonstrate the potential applicability of this method.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Organic
An-Qi Cheng, Zeng-Hua Wu, Huai-Lan Yang, Wei-Liang Duan
Summary: A Pd-catalyzed asymmetric phosphination of alpha,beta-unsaturated sulfonyl fluorides was developed, resulting in a series of tertiary phosphorus compounds in high yields and enantioselectivities up to 99% ee. The chiral adduct can be further converted into chiral phosphine sulfonic acid as the ligand for the arene Ru metal complex.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Organic
Kristina C. Probasco, Michael P. Jennings
Summary: The NXS-mediated halogenation reaction of (E)-alpha-trimethylsilyl-beta-alkyl(aryl)-alpha,beta-unsaturated esters in DMF resulted in the formation of (Z)-beta-substituted-alpha-halogenated-alpha,beta-unsaturated ester products with moderate to high yields. The reaction mechanism involves an initial halonium cation intermediate and regioselective ring opening with DMF, leading to the stereoselective formation of vinylic bromo- and chloroesters.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Saki Inatomi, Yuta Takayanagi, Kento Watanabe, Akinori Toita, Hiroyuki Yamakoshi, Seiichi Nakamura
Summary: The scope and limitations of the diastereoselective 1,4-addition reaction of primary alcohols to gamma-alkoxy-alpha,beta-unsaturated esters were investigated, with sodium alkoxides showing good to excellent syn-selectivity. The use of glycerol derivatives as nucleophiles did not show stereoselectivity. Cyclic acetal protection was found to be crucial for the reaction to proceed.
SYNTHESIS-STUTTGART
(2021)
Article
Chemistry, Multidisciplinary
Daniel Rozsar, Michele Formica, Ken Yamazaki, Trevor A. Hamlin, Darren J. Dixon
Summary: This paper describes a metal-free catalytic intermolecular enantioselective Michael addition to unactivated alpha,beta-unsaturated amides. Consistently high enantiomeric excesses and yields were obtained under mild reaction conditions, using a novel squaramide-based bifunctional iminophosphorane catalyst. Computational analysis revealed the origin of the high enantiofacial selectivity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Ze-Kuan Zhang, Wen-Yan Xu, Tian-Jun Gong, Yao Fu
Summary: This study presents a controllable fluorination technique for biomass-based 5-HMF and its derivatives, synthesizing a series of mono-fluoromethyl, difluoromethyl, and acylfluoro-substituted furan compounds. These fluoro-substituted furan compounds can be further transformed to prepare drug analogs, offering a novel approach for the high-value utilization of biomass molecules.
Article
Chemistry, Organic
Xiang-Shuai Liu, Yao Li, Xin Li
Summary: A highly efficient asymmetric 1,2-allylation reaction of beta,gamma-unsaturated alpha-ketoesters was achieved using a Bi(OAc)(3)/chiral phosphoric acid catalyst system under mild conditions. Additionally, an asymmetric formal 1,4-allylation reaction was realized through a one-pot process, yielding homoallylic tertiary alcohols and gamma-allyl-alpha-ketoesters with good yields and excellent enantioselectivities. Density functional theory calculations were used to interpret the high enantioselectivity observed in the reactions.
Article
Chemistry, Organic
Pingshun Zhang, Linjie Yang, Wanzhi Chen, Miaochang Liu, Huayue Wu
Summary: An efficient method for the synthesis of [1,4]thiazino[4,3-alpha]indole derivatives was developed using sodium chlorodifluoroacetate and elemental sulfur as the difluoromethylthiolating reagent system. The sequential transformation process selectively formed four bonds including one C-N, two C-S, and one C-C bonds in good yields.
Article
Chemistry, Multidisciplinary
Ryo Tanaka, Yuki Hirata, Masahiro Kojima, Tatsuhiko Yoshino, Shigeki Matsunaga
Summary: This study reports a C-H bond addition reaction of 2-phenylpyridine derivatives with alpha,beta-unsaturated carboxylic acids catalyzed by Cp*Rh(iii)/BH3 center dot SMe2. The activation of C-H bonds with the rhodium catalyst and activation of alpha,beta-unsaturated carboxylic acids with the boron catalyst cooperatively work, and a BINOL-urea hybrid ligand significantly improved the reactivity. With the optimized hybrid catalytic system, various beta-disubstituted carboxylic acids were obtained under mild reaction conditions.
CHEMICAL COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Xinyi Wang, Trevor J. Wilson, Christopher R. Maroon, Jeffrey A. Laub, Savannah E. Rheingold, Konstantinos D. Vogiatzis, Brian K. Long
Summary: Natural gas production and utilization have increased significantly in recent years, necessitating improved methods for purification. This study focuses on the development of polymeric materials for natural gas purification and demonstrates that incorporating fluoroalkoxysilyl substituents can enhance CO2/CH4 permselectivity. The findings suggest that the observed increase in selectivity is primarily due to improved CO2 sorption in the fluorine-containing polymers.
ACS APPLIED POLYMER MATERIALS
(2022)
Article
Biochemical Research Methods
Deepti Katiyar, Rashmi Saxena, Abhishek Kumar, Surya Prakash, Abhay Bhardwaj, Priya Bansal
Summary: This article presents a literature metasynthesis on Bryonia laciniosa, highlighting its phytochemical and therapeutic profile. The plant exhibits a range of pharmacological activities including antimicrobial, anti-inflammatory, analgesic, antipyretic, anticonvulsant, anti-asthmatic, anticancer, antioxidant, antidiabetic, and aphrodisiac effects.
COMBINATORIAL CHEMISTRY & HIGH THROUGHPUT SCREENING
(2023)
Article
Chemistry, Physical
Dean E. Glass, Vicente Galvan, Marc Iulliucci, G. K. Surya Prakash
Summary: This study investigates the role of partially fluorinated carbon (CFx) supported platinum nanoparticles as electrodes in a proton exchange membrane fuel cell (PEMFC) for hydrogen fuel cell applications. The results show that CFx, as a platinum catalyst support, exhibits better oxygen reduction reaction (ORR) kinetics compared to the widely used Vulcan Carbon (XC-72R). CFx catalysts display higher ORR kinetics at lower platinum loadings, while XC-72R displays higher kinetics at higher platinum loadings. The PEMFC tests reveal that CFx supported catalysts exhibit a 20% increase in fuel cell performance and an 11% decrease in charge transfer resistance compared to XC-72R supported catalysts. Furthermore, using CFx as the support for both anode and cathode electrodes leads to a 15% increase in power density compared to XC-72R supported catalysts.
JOURNAL OF POWER SOURCES
(2022)
Article
Geosciences, Multidisciplinary
K. A. Kamesh Raju, V. Yatheesh, A. Srinivas Rao, L. Surya Prakash, Durbar Ray, Abhay Mudholkar, Kiranmai Samudrala, Nico Augustin, P. John Kurian
Summary: The topographic fabric of the rift valley floor in a segment of the slow-spreading Central Indian Ridge was analyzed using data obtained by the autonomous underwater vehicle (AUV) Abyss. The AUV dives revealed features such as a lava lake, a cratered volcano, an oceanic core complex (OCC), and a foot wall volcanic complex. The analysis of CTD data indicated the presence of temperature spikes related to leaky venting of fluids from a linear fissure on the seafloor.
GEO-MARINE LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Christopher J. J. Koch, Anushan Alagaratnam, Alain Goeppert, G. K. Surya Prakash
Summary: Cellulose, a major component of plant matter, is a potential target for biomass conversion to fuels. Direct conversion of cellulose to methane using nickel-based catalysts often faces challenges due to carbon agglomeration. The addition of rare-earth metals as promoters increases cellulose conversion to methane, but leads to catalyst deactivation in the form of nickel-rare-earth-carbon nanoparticles. Adding zinc metal as an additional promoter eliminates carbon agglomeration and improves methane yields. This study reports an 81% methane yield from cellulose within 48 hours using a Ni/Zn/Y/Al2O3 catalyst, at 225 degrees C and under 50 bar H-2 pressure.
ISRAEL JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Organic
Xanath Ispizua-Rodriguez, Vinayak Krishnamurti, Vanessa Carpio, Colby Barrett, G. K. Surya Prakash
Summary: An efficient method for direct difluoromethylation of terminal alkynes and desilylation-difluoromethylation of (trimethylsilyl)acetylenes is reported. Copper-catalyzed transformation using a (difluoromethyl)zinc reagent and an organic oxidant provides access to a variety of structurally diverse CF2H alkynes in good yields. The synthetic utility of these (difluoromethyl)alkynes is demonstrated by selected cycloaddition reactions, and a slight modification to the reaction conditions allows the selective preparation of a 2-difluoromethylindole.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Geochemistry & Geophysics
P. Linsy, L. Surya Prakash, Parijat Roy, Muhammad Shuhail, P. John Kurian
Summary: This study conducted a detailed investigation on the geochemical characteristics of iron using a sediment core from the eastern Southwest Indian Ridge. The results revealed that a significant amount of hydrothermal iron precipitates near the source and plays a crucial role in oceanic elemental cycling.
Article
Chemistry, Multidisciplinary
Daniel Lin, Juan Pablo de los Rios, G. K. Surya Prakash
Summary: N-(difluoromethyl)amino (-NCF2H) compounds have unique and underexplored physiochemical properties, but lack structural diversity due to a shortage of efficient installation protocols. This study presents a new shelf-stable pyridinium reagent that enables direct installation of the N-(difluoromethyl)sulfonamide moiety onto (hetero)arenes and alkenes, diversifying the aryl and alkyl NCF2H compounds. The protocol utilizes blue light photoredox catalysis, demonstrating broad functional group tolerance and excellent chemoselectivity. Additional transformations and applicability towards a photoredox continuous flow protocol are also shown.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Chemistry, Multidisciplinary
Daniel Lin, Matthew Coe, Vinayak Krishnamurti, Xanath Ispizua-Rodriguez, G. K. Surya Prakash
Summary: In recent years, many reagents and protocols have been developed for efficient fluorofunctionalization of various scaffolds. Organofluorine chemistry and visible light-mediated synthesis have played complementary roles in expanding the fields and discovering new bioactive compounds. This review focuses on the recent advances made in visible light-mediated fluoroalkylation and heteroatom centered radical generation.
Article
Engineering, Electrical & Electronic
Vivek Singh Baghel, Surya Prakash
Summary: Biometric authentication systems are widely used for securing various applications, including consumer electronics devices. However, the increased use of biometric authentication poses the risk of permanently compromising a person's biometric identity, as biometric data cannot be changed. This paper proposes a secure and non-invertible fingerprint based user template protection technique, which utilizes 3D-grid mapping and Discrete Fourier Transform. The technique is evaluated using publicly available fingerprint databases and demonstrates superior results compared to state-of-the-art techniques.
IEEE TRANSACTIONS ON CONSUMER ELECTRONICS
(2023)
Article
Chemistry, Inorganic & Nuclear
Alexander Knieb, Vinayak Krishnamurti, Ziyue Zhu, G. K. Surya Prakash
Summary: A metal-free protocol for the synthesis of monofluoromethylarenes using diaryliodonium salts and fluorobis (phenylsulfonyl)methane (FBSM) is presented as an alternative to traditional metal-mediated monofluoromethylation reactions. Inexpensive and accessible starting materials are utilized, and the target products are obtained with excellent yields (up to 97%) and good functional group tolerance. The counter anion of the iodonium species is found to significantly affect the reaction yield, and the ionic nature of the reaction mechanism is elucidated using Hammett's linear free energy analysis, supported by control experiments.
JOURNAL OF FLUORINE CHEMISTRY
(2023)
Article
Chemistry, Physical
Christopher J. Koch, Zohaib Suhail, Alain Goeppert, G. K. Surya Prakash
Summary: Rising CO2 levels enhance the greenhouse gas effect in the atmosphere, but CO2 can be captured and converted to methane using hydroxide salts and catalysts.
Review
Chemistry, Inorganic & Nuclear
Thomas Mathew, Socrates B. Munoz, Olivier Forni, Alain Tressaud, G. K. Surya Prakash
Summary: Fluorine plays a significant role in the geochemical world, affecting the properties of chemical compounds both on Earth and in extraterrestrial regions. The study of its origin and abundance is crucial for understanding its relevance to terrestrial chemistry and its presence in other planets and star-forming galaxies. The literature review reveals the presence of fluorine in various extraterrestrial regions, indicating its ubiquity in the stellar and interstellar medium. Further research on the fluorine effect in extraterrestrial atmospheres is important due to its growing influence on Earth.
JOURNAL OF FLUORINE CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Bradley M. Lipka, Daniel S. Honeycutt, Gregory M. Bassett, Taylor N. Kowal, Max Adamczyk, Zachary C. Cartnick, Vincent M. Betti, Jacob M. Goldberg, Fang Wang
Summary: Rapid bond-forming reactions are crucial for efficient bioconjugation. We propose a simple and practical strategy for facilitating ultra-rapid electrophilic cysteine arylation, which exhibits high rate constants and allows for fast and selective bioconjugation to obtain functionalized peptides and proteins with high conversion and purity.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Christopher J. Koch, Anushan Alagaratnam, Alain Goeppert, G. K. Surya Prakash
Summary: Phosphate salts have been studied as carbon dioxide capture reagents, but their role in the direct conversion of captured carbon dioxide to hydrogenated products is not well understood. In this study, we report the conversion of captured carbon dioxide to methane in a phosphate-assisted system. While a nickel-based catalyst showed strong inhibition due to unwanted interaction with phosphate species, 5% Ru/Al2O3 catalyst achieved 100% conversion of captured CO2 to methane after 6 hours under 50 bar H-2 at 200 degrees C. The 5% Ru/Al2O3 catalyst also maintained its reactivity over multiple capture/hydrogenation cycles.
SUSTAINABLE ENERGY & FUELS
(2023)
Article
Chemistry, Multidisciplinary
Christopher J. Koch, Vicente Galvan, Alain Goeppert, G. K. Surya Prakash
Summary: The direct conversion of inorganic carbonate salts into methane using Ni/Al2O3 and Ni/CaAl2O4 catalysts under 50 bar of hydrogen at a temperature of 225 degrees C is reported. Water improved the conversion rate and the Ni/Al2O3 catalyst retained 99% of its activity after five hydrogenation cycles. The metal hydroxide was regenerated and reused to capture CO2 for subsequent reactions. Compared to the sequential approach, this integrated route offers energetic and economic benefits for carbon capture and conversion.
