Article
Chemistry, Organic
Asmita Mondal, Luis R. Domingo, Nivedita Acharjee
Summary: The influence of ethylene substitution and tether length on the selectivity and reactivity of intramolecular [3+2] cycloaddition reactions in cyclic nitrones was studied using the Molecular Electron Density theory. The introduction of electron withdrawing substituents at the alkene moiety decreases the activation barrier, leading to more facile reactions. In addition, the regioselectivity of the reactions is influenced by the number of methylene units between the nitrone and ethylene frameworks.
JOURNAL OF PHYSICAL ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Bhaskar Mondal, Luis R. Domingo, Haydar A. Mohammad-Salim, Nivedita Acharjee
Summary: In this study, the [3 + 2] cycloaddition (32CA) reactions of C-(4-methoxyphenyl)-N-phenyl nitrile imine (NI) with a series of ethylene derivatives were investigated using Molecular Electron Density Theory (MEDT). The research showed that the electron-withdrawing substituents in the ethylene accelerated the forward electron density flux (FEDF) in the 32CA reactions.
COMPUTATIONAL AND THEORETICAL CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Eveline H. H. Tiekink, Pascal Vermeeren, Trevor A. A. Hamlin
Summary: We investigated the uncatalyzed and Lewis acid (LA)-catalyzed cycloaddition reaction between tropone and 1,1-dimethoxyethene using dispersion-corrected relativistic density functional theory (DFT). The LA catalysts BF3, B(C6H5)(3), and B(C6F5)(3) effectively accelerated both [4+2] and [8+2] cycloaddition reactions by lowering the activation barrier by up to 12 kcal mol(-1) compared to the uncatalyzed reaction. Our study revealed that the LA catalyst promoted the cycloaddition reaction pathways through LUMO-lowering catalysis and demonstrated that Pauli-lowering catalysis is not always the operative mechanism in cycloaddition reactions. Selecting the appropriate LA catalyst allowed for regiocontrol of the cycloaddition: B(C6H5)(3) yielded the [8+2] adduct while B(C6F5)(3) produced the [4+2] adduct. The regioselectivity shift was found to be due to the LA's ability to absorb distortion and adopt a trigonal pyramidal geometry around the boron atom.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Physical
Nizar El Guesmi, Essam M. Hussein, Ziad Moussa, Afnan H. Alkhuzaee, Abdullah Y. A. Alzahrani, Rabab S. Jassas, Munirah M. Al-Rooqi, Rami J. Obaid, Saleh A. Ahmed
Summary: An efficient and catalyst-free method for synthesizing fused polyheterocyclic pyrene-grafted dispiro-pyrrolidine oxindolines is reported. The regio- and stereochemistry of the cycloadducts were determined using NMR spectroscopy, and the mechanism and regioselectivity of the reaction were discussed based on computational calculations.
JOURNAL OF MOLECULAR STRUCTURE
(2022)
Article
Biochemistry & Molecular Biology
Sabir A. Mohammed Salih, Huda A. Basheer, Jesus Vicente de Julian-Ortiz, Haydar A. Mohammad-Salim
Summary: This study investigated the [3+2] cycloaddition reactions of N-methyl-C-4-methyl phenyl-nitrone 1 and 2-propynamide 2 using molecular electron density theory. The reactions produced four different products through irreversible pathways. The formation of cycloadduct 6 had a slightly increased polar character, observed through global electron density transfer.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Physical
Haydar A. Mohammad-Salim, Nivedita Acharjee, Luis R. Domingo, Hassan H. Abdallah
Summary: The study investigated the [3 + 2] cycloaddition reactions of 1-pyrroline-1-oxide with acetylene and a series of symmetrically disubstituted acetylenes. These reactions proceed through a one-step mechanism with different activation enthalpies, and are irreversible, forming new C-C and C-O single bonds.
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY
(2021)
Article
Biochemical Research Methods
Mohamed Oussama Zouaghi, Mohamed Yassine Doggui, Youssef Arfaoui
Summary: The theoretical study on the regio- and stereoselectivities of [3 + 2] cycloaddition reactions of nitrones with substituted alkene has been conducted using density functional theory. The favored pathway was determined to be the endo approach based on activation energy calculations and FMO model analysis.
JOURNAL OF MOLECULAR GRAPHICS & MODELLING
(2021)
Article
Chemistry, Organic
Kelvin J. Y. Wu, Amy E. Benedetto, Andrew G. Myers
Summary: The regioselectivity of a [3+2] dipolar cycloaddition reaction between a stabilized azomethine ylide and an electron-deficient dipolarophile is contrary to a previous report in this journal.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Luis R. Domingo, Mar Rios-Gutierrez, Nivedita Acharjee
Summary: The BF3 Lewis acid catalyzed [3+2] cycloaddition reaction was studied using molecular electron density theory, and it was found that BF3 acts as a catalyst, increasing the polarity of the reaction and decreasing the activation enthalpy.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Nicolaj Inunnguaq Jessen, Joseph A. Izzo, Marek S. Modlinski, Giulio Bertuzzi, Karl Anker Jorgensen
Summary: The development of higher-order cycloadditions has been limited due to the need for highly conjugated and reactive pi-systems. Recent research shows that organocatalysis can be an efficient mediator to overcome these challenges. Computational studies have also found that the impact of benzofusions on higher-order cycloadditions can be explained by changes in energy barriers.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Physical
Maksym Fizer, Mikhailo Slivka, Nataliya Korol, Oksana Fizer
Summary: The study investigated the regioselectivity of alkylation of 1,2,4-triazole-3-thiones, comparing experimentally observed NMR chemical shifts with those predicted by DFT calculations. The results showed that S-alkylation is more selective under neutral conditions, and reactivity descriptors like HOMO, ELF, electrophilic Fukui function, and partial charges were considered to explain the regioselectivity and product structures accurately.
JOURNAL OF MOLECULAR STRUCTURE
(2021)
Article
Chemistry, Applied
Tsai-Hui Lung, Yi-Ru Chen, Chen-Ling Chang, Wey-Chyng Jeng, Pei-Shan Wu, Sandip Sambhaji Vagh, Gangababu Marri, Yi-Fang Lin, Wenwei Lin
Summary: A catalyst-controlled diversity-oriented synthesis of spirohydroquinoline-indandiones and 3-methylenehydroquinoline-indandiones was reported using ortho-sulfonamidophenyl-substituted para-quinone methides and allylidene-indandiones. Organobases such as DMAP or TMG were utilized to selectively control the reaction pathway, resulting in products with yields of 40-99% and excellent diastereoselectivities. Mechanistic studies revealed that spirohydroquinoline-indandione was the kinetic product, which underwent an unusual base-initiated 1,3-nitrogen rearrangement process to afford 3-methylenehydroquinoline-indandione in the presence of TMG.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Physical
Giorgio Molteni, Alessandro Ponti
Summary: In this study, the accuracy of predicting the regioselectivity of uncatalyzed thermal azide 1,3-DCs using DFT calculations was investigated. Benchmark data was established and compared with results obtained using density functional approximations (DFAs). The study identified the key features for accurate regioselectivity and suggested potential improvements for future research.
Article
Chemistry, Multidisciplinary
Barsali Banerjee, Nivedita Acharjee, Debnath Palit
Summary: The intramolecular [3 + 2] cycloaddition reactions of allenic nitrones were studied using molecular electron density theory (MEDT). These reactions showed high activation free energies in ethanol, indicating a non-polar character and following a one-step mechanism. The presence of different methylene units affected the cyclization selectivity, in agreement with experimental outcomes. Topological analysis revealed non-covalent interactions at the interatomic bonding regions of the transition states.
STRUCTURAL CHEMISTRY
(2023)
Article
Chemistry, Physical
Esseddik Elqars, Ali Oubella, Mouhi Eddine Hachim, Said Byadi, Aziz Auhmani, Mohamed Guennoun, Abdelhafid Essadki, Abdelkhalek Riahi, Anthony Robert, Moulay Youssef Ait Itto, Taibi Nbigui
Summary: A novel mono-isoxazole compound was synthesized and studied for its anti-corrosion effect on carbon steel in acidic environment. The compound exhibited excellent inhibition performance and effectively protected the carbon steel from corrosion at a certain concentration.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Chemistry, Physical
Haydar A. Mohammad-Salim, Nivedita Acharjee, Hassan H. Abdallah
Summary: This study presents a molecular electron density theory analysis of [3 + 2] cycloaddition reactions, predicting a zwitter-ionic character for the cyclic nitrone and global electronic flux from the nucleophilic nitrone to the electrophilic nitrile functions. The reaction pathways and mechanisms are determined based on bonding evolution theory and topological studies at transition states.
THEORETICAL CHEMISTRY ACCOUNTS
(2021)
Article
Chemistry, Physical
Sabir A. Mohammed Salih, Huda A. Basheer, Haydar A. Mohammad-Salim
Summary: The [3+2] cycloaddition reaction of N-methyl-C-(4-hydroxylphenyl) nitrone and maleic anhydride was investigated using molecular electron density theory. The reaction can undergo two different stereo- and stereoisomeric paths to form two different products. It was found that the reaction is exergonic and the endo stereochemical pathway is more thermodynamically stable than the exo pathway.
THEORETICAL CHEMISTRY ACCOUNTS
(2022)
Article
Biochemistry & Molecular Biology
Sabir A. Mohammed Salih, Huda A. Basheer, Jesus Vicente de Julian-Ortiz, Haydar A. Mohammad-Salim
Summary: This study investigated the [3+2] cycloaddition reactions of N-methyl-C-4-methyl phenyl-nitrone 1 and 2-propynamide 2 using molecular electron density theory. The reactions produced four different products through irreversible pathways. The formation of cycloadduct 6 had a slightly increased polar character, observed through global electron density transfer.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Multidisciplinary
Nivedita Acharjee, Haydar A. Mohammad-Salim, Mrinmoy Chakraborty
Summary: The regioselective synthesis of a potent antiviral sugar nucleoside isoxazole analogue has been studied using molecular electron density theory. The reaction is more favorable in low polar solvents and involves non-covalent intermolecular interactions before the formation of new bonds.
JOURNAL OF THE SERBIAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Haydar A. Mohammad-Salim, Huda Ahmed Basheer, Hassan H. Abdallah, Abdellah Zeroual, Lazgin Abdi Jamil
Summary: The [3+2] cycloaddition reactions of N-benzylcyclohexylnitrone with methyl-3-butenoate were studied using molecular electron density theory. The zwitterionic reactions occur through a one-step mechanism and result in the formation of four different products. Analysis using global electron density transfer revealed differences in activation enthalpy among the reaction paths. Bonding evolution theory suggests the formation of new covalent bonds in the transition states of these reactions.
NEW JOURNAL OF CHEMISTRY
(2021)
Article
Multidisciplinary Sciences
Haydar A. Mohammad-Salim, Hassan H. Abdallah
ARO-THE SCIENTIFIC JOURNAL OF KOYA UNIVERSITY
(2019)
