1
|
Moriyama K, Oka Y. Enantioselective Cascade Michael/Hemiaminal Formation of α,β-Unsaturated Iminoindoles with Aldehydes Using a Chiral Aminomethylpyrrolidine Catalyst Bearing a SO 2C 6F 5 Group as a Strongly Electron Withdrawing Arylsulfonyl Group. ACS Catal 2022. [DOI: 10.1021/acscatal.2c01182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Katsuhiko Moriyama
- Department of Chemistry, Graduate School of Science and Soft Molecular Activation Research Center, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Yukari Oka
- Department of Chemistry, Graduate School of Science and Soft Molecular Activation Research Center, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| |
Collapse
|
2
|
Das M, Gogoi AR, Sunoj RB. Molecular Insights on Solvent Effects in Organic Reactions as Obtained through Computational Chemistry Tools. J Org Chem 2021; 87:1630-1640. [PMID: 34752092 DOI: 10.1021/acs.joc.1c02222] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Molecular understanding of the role of protic solvents in a gamut of organic transformations can be developed using density functional and ab initio computational studies focused on the reaction mechanism. Inclusion of explicit solvent molecules in the vital TSs has been proven to be valuable toward improving the energetic estimates of organocatalytic as well as transition-metal-catalyzed organic reactions. Herein, we provide an overview of the importance of an explicit-implicit solvation model using a number of interesting examples.
Collapse
Affiliation(s)
- Manajit Das
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Achyut Ranjan Gogoi
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Raghavan B Sunoj
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
3
|
Oka Y, Tsuzuki S, Moriyama K. Chiral anthranilic pyrrolidine as custom-made amine catalyst for enantioselective Michael reaction of nitroalkenes with carbonyl compounds. Chem Commun (Camb) 2021; 57:11457-11460. [PMID: 34632990 DOI: 10.1039/d1cc04453b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A chiral anthranilic pyrrolidine catalyst as a custom-made amine-catalyst was developed for the enantio- and diastereo selective Michael reaction of nitroalkenes with carbonyl compounds. In particular, a peptide-like catalyst in which an α-amino acid is attached to the anthranilic acid skeleton induced the high stereoselectivity of the reaction with aldehydes. Studies of the reaction mechanism indicated that the catalyst exhibits a divergent stereocontrol in the reaction, namely, steric control by a 2-substituted group on the catalyst and hydrogen-bonding control by a carboxylic acid group on the catalyst.
Collapse
Affiliation(s)
- Yukari Oka
- Department of Chemistry, Graduate School of Science and Soft Molecular Activation Research Center, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
| | - Seiji Tsuzuki
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-8656, Japan
| | - Katsuhiko Moriyama
- Department of Chemistry, Graduate School of Science and Soft Molecular Activation Research Center, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
| |
Collapse
|
4
|
Das T, Mohapatra S, Mishra NP, Nayak S, Raiguru BP. Recent Advances in Organocatalytic Asymmetric Michael Addition Reactions to α, β‐Unsaturated Nitroolefins. ChemistrySelect 2021. [DOI: 10.1002/slct.202100679] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Tapaswini Das
- Organic Synthesis Laboratory, Department of Chemistry Ravenshaw University Cuttack 753003, Odisha India
| | - Seetaram Mohapatra
- Organic Synthesis Laboratory, Department of Chemistry Ravenshaw University Cuttack 753003, Odisha India
| | - Nilima P. Mishra
- Organic Synthesis Laboratory, Department of Chemistry Ravenshaw University Cuttack 753003, Odisha India
| | - Sabita Nayak
- Organic Synthesis Laboratory, Department of Chemistry Ravenshaw University Cuttack 753003, Odisha India
| | - Bishnu P. Raiguru
- Organic Synthesis Laboratory, Department of Chemistry Ravenshaw University Cuttack 753003, Odisha India
| |
Collapse
|
5
|
Jain S, Vanka K. The Effect of Solvent-Substrate Noncovalent Interactions on the Diastereoselectivity in the Intramolecular Carbonyl-Ene and the Staudinger [2 + 2] Cycloaddition Reactions. J Phys Chem A 2020; 124:8019-8028. [PMID: 32894951 DOI: 10.1021/acs.jpca.0c05738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Noncovalent interactions (NCIs) have been identified as important contributing factors for determining selectivity in organic transformations. However, cases where NCIs between solvents and substrates are responsible for a major extent for determining selectivity are rare. The current computational study with density functional theory identifies two important transformations where this is the case: the intramolecular carbonyl-ene reaction and the Staudinger [2 + 2] cycloaddition reaction. In both cases, the role of explicit solvent molecules interacting noncovalently with the substrate has been taken into account. Calculations indicate that the diastereomeric ratio would be 95.0:5.0 for the formation of tricyclic tetrahydrofuran diastereomers via the intramolecular carbonyl-ene reaction and 94.0:6.0 for the formation of the triflone diastereomers via the Staudinger [2 + 2] cycloaddition reaction, which corroborates with the experiment. Interestingly, in both the cases, the calculations indicate that noninclusion of explicit solvent molecules would lead to only a small difference between the competing transition states, which leads to the conclusion that solvent-substrate NCIs are the major cause for diastereoselectivity in both the cases considered.
Collapse
Affiliation(s)
- Shailja Jain
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Kumar Vanka
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| |
Collapse
|
6
|
Kusama H. Interaction of tris(4-anisyl)amine mediator in dye-sensitized solar cells. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2019.112150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
7
|
Kusama H. Interaction between dyes and SeCN−–(SeCN)2 redox mediator in dye-sensitized solar cells. J Photochem Photobiol A Chem 2019. [DOI: 10.1016/j.jphotochem.2019.03.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
8
|
Concerted Catalysis by Nanocellulose and Proline in Organocatalytic Michael Additions. Molecules 2019; 24:molecules24071231. [PMID: 30934821 PMCID: PMC6480416 DOI: 10.3390/molecules24071231] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 03/23/2019] [Accepted: 03/27/2019] [Indexed: 12/25/2022] Open
Abstract
Cellulose nanofibers (CNFs) have recently attracted much attention as catalysts in various reactions. Organocatalysts have emerged as sustainable alternatives to metal-based catalysts in green organic synthesis, with concerted systems containing CNFs that are expected to provide next-generation catalysis. Herein, for the first time, we report that a representative organocatalyst comprising an unexpected combination of 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)-oxidized CNFs and proline shows significantly enhanced catalytic activity in an asymmetric Michael addition.
Collapse
|
9
|
Gorde AB, Ramapanicker R. d-Prolyl-2-(trifluoromethylsulfonamidopropyl)pyrrolidine: An Organocatalyst for Asymmetric Michael Addition of Aldehydes to β-Nitroalkenes at Ambient Conditions. J Org Chem 2019; 84:1523-1533. [PMID: 30609351 DOI: 10.1021/acs.joc.8b02945] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Amol B. Gorde
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Ramesh Ramapanicker
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| |
Collapse
|
10
|
Han J, Zhang Y, Wu XY, Wong HNC. Chiral iminophosphorane catalyzed asymmetric sulfenylation of 4-substituted pyrazolones. Chem Commun (Camb) 2019; 55:397-400. [DOI: 10.1039/c8cc09049a] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
An excellent level of enantioselectivity in asymmetric sulfenylation of 4-substituted pyrazolones was achieved with chiral iminophosphorane as organocatalyst under the continuum solvation conditions. The use of hydrocarbon solvents enabled to enhance the enantiomeric excesses of the desired 4-phenylthio-pyrazol-5-ones (up to 99% ee).
Collapse
Affiliation(s)
- Jianwei Han
- Key Laboratory for Advanced Materials
- Institute of Fine Chemicals
- School of Chemistry & Molecular Engineering
- East China University of Science and Technology
- Shanghai 200237
| | - Yanxia Zhang
- Key Laboratory for Advanced Materials
- Institute of Fine Chemicals
- School of Chemistry & Molecular Engineering
- East China University of Science and Technology
- Shanghai 200237
| | - Xin-Yan Wu
- Key Laboratory for Advanced Materials
- Institute of Fine Chemicals
- School of Chemistry & Molecular Engineering
- East China University of Science and Technology
- Shanghai 200237
| | - Henry N. C. Wong
- Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis
- Shanghai Institute of Organic Chemistry
- The Chinese Academy of Sciences
- Shanghai 200032
- China
| |
Collapse
|
11
|
Kang XM, Wang WM, Yao LH, Ren HX, Zhao B. Solvent-dependent variations of both structure and catalytic performance in three manganese coordination polymers. Dalton Trans 2018; 47:6986-6994. [DOI: 10.1039/c8dt01103f] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three new Mn-based MOFs have been prepared, and a 3D framework can act as an efficient and recycled catalyst in CO2 cycloaddition with different epoxides.
Collapse
Affiliation(s)
- Xiao-Min Kang
- College of Chemistry and Key Laboratory of Advanced Energy Material Chemistry
- Nankai University
- Tianjin
- China
| | - Wen-Min Wang
- College of Chemistry and Key Laboratory of Advanced Energy Material Chemistry
- Nankai University
- Tianjin
- China
| | - Lin-Hong Yao
- College of Chemistry and Key Laboratory of Advanced Energy Material Chemistry
- Nankai University
- Tianjin
- China
| | - Hong-Xia Ren
- College of Chemistry and Key Laboratory of Advanced Energy Material Chemistry
- Nankai University
- Tianjin
- China
| | - Bin Zhao
- College of Chemistry and Key Laboratory of Advanced Energy Material Chemistry
- Nankai University
- Tianjin
- China
| |
Collapse
|
12
|
Husch T, Seebach D, Beck AK, Reiher M. Rigorous Conformational Analysis of Pyrrolidine Enamines with Relevance to Organocatalysis. Helv Chim Acta 2017. [DOI: 10.1002/hlca.201700182] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Tamara Husch
- Laboratorium für Physikalische Chemie ETH Zürich Vladimir‐Prelog‐Weg 3 8093 Zürich Switzerland
| | - Dieter Seebach
- Laboratorium für Organische Chemie ETH Zürich Vladimir‐Prelog‐Weg 2 8093 Zürich Switzerland
| | - Albert K. Beck
- Laboratorium für Organische Chemie ETH Zürich Vladimir‐Prelog‐Weg 2 8093 Zürich Switzerland
| | - Markus Reiher
- Laboratorium für Physikalische Chemie ETH Zürich Vladimir‐Prelog‐Weg 3 8093 Zürich Switzerland
| |
Collapse
|
13
|
Yuan H, Zhang J. Mechanistic insights on DBU catalyzedβ-amination of nbs to chalcone driving by water: Multiple roles of water. J Comput Chem 2017; 38:438-445. [DOI: 10.1002/jcc.24700] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 12/01/2016] [Accepted: 12/01/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Haiyan Yuan
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Advanced Energy Materials Research Center, Faculty of Chemistry; Northeast Normal University; Renmin Street 5268# Changchun 130024 China
| | - Jingping Zhang
- Jilin Province Key Laboratory of Organic Functional Molecular Design & Synthesis, Advanced Energy Materials Research Center, Faculty of Chemistry; Northeast Normal University; Renmin Street 5268# Changchun 130024 China
| |
Collapse
|
14
|
Borges-González J, Feher-Voelger A, Crisóstomo FP, Morales EQ, Martín T. Tetrahydropyran-Based Hybrid Dipeptides as Asymmetric Catalysts for Michael Addition of Aldehydes to β-Nitrostyrenes. Adv Synth Catal 2017. [DOI: 10.1002/adsc.201601193] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Jorge Borges-González
- Instituto de Productos Naturales y Agrobiología-CSIC; Avda. Astrofísico Francisco Sánchez, 3 38206 La Laguna, S/C de Tenerife Spain
| | - Andrés Feher-Voelger
- Instituto de Productos Naturales y Agrobiología-CSIC; Avda. Astrofísico Francisco Sánchez, 3 38206 La Laguna, S/C de Tenerife Spain
| | - Fernando Pinacho Crisóstomo
- Instituto de Productos Naturales y Agrobiología-CSIC; Avda. Astrofísico Francisco Sánchez, 3 38206 La Laguna, S/C de Tenerife Spain
- Instituto Universitario de Bio-Orgánica “Antonio González”, CIBICAN; Avda. Astrofísico Francisco Sánchez, 2 38206 La Laguna, S/C de Tenerife Spain
| | - Ezequiel Q. Morales
- Instituto de Productos Naturales y Agrobiología-CSIC; Avda. Astrofísico Francisco Sánchez, 3 38206 La Laguna, S/C de Tenerife Spain
| | - Tomás Martín
- Instituto de Productos Naturales y Agrobiología-CSIC; Avda. Astrofísico Francisco Sánchez, 3 38206 La Laguna, S/C de Tenerife Spain
- Instituto Universitario de Bio-Orgánica “Antonio González”, CIBICAN; Avda. Astrofísico Francisco Sánchez, 2 38206 La Laguna, S/C de Tenerife Spain
| |
Collapse
|
15
|
Gao T, Li H, Li W, Li L, Fang C, Li H, Hu L, Lu Y, Su ZM. A machine learning correction for DFT non-covalent interactions based on the S22, S66 and X40 benchmark databases. J Cheminform 2016; 8:24. [PMID: 27148408 PMCID: PMC4855356 DOI: 10.1186/s13321-016-0133-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 04/11/2016] [Indexed: 12/13/2022] Open
Abstract
Background Non-covalent interactions (NCIs) play critical roles in supramolecular chemistries; however, they are difficult to measure. Currently, reliable computational methods are being pursued to meet this challenge, but the accuracy of calculations based on low levels of theory is not satisfactory and calculations based on high levels of theory are often too costly. Accordingly, to reduce the cost and increase the accuracy of low-level theoretical calculations to describe NCIs, an efficient approach is proposed to correct NCI calculations based on the benchmark databases S22, S66 and X40 (Hobza in Acc Chem Rev 45: 663–672, 2012; Řezáč et al. in J Chem Theory Comput 8:4285, 2012). Results A novel type of NCI correction is presented for density functional theory (DFT) methods. In this approach, the general regression neural network machine learning method is used to perform the correction for DFT methods on the basis of DFT calculations. Various DFT methods, including M06-2X, B3LYP, B3LYP-D3, PBE, PBE-D3 and ωB97XD, with two small basis sets (i.e., 6-31G* and 6-31+G*) were investigated. Moreover, the conductor-like polarizable continuum model with two types of solvents (i.e., water and pentylamine, which mimics a protein environment with ε = 4.2) were considered in the DFT calculations. With the correction, the root mean square errors of all DFT calculations were improved by at least 70 %. Relative to CCSD(T)/CBS benchmark values (used as experimental NCI values because of its high accuracy), the mean absolute error of the best result was 0.33 kcal/mol, which is comparable to high-level ab initio methods or DFT methods with fairly large basis sets. Notably, this level of accuracy is achieved within a fraction of the time required by other methods. For all of the correction models based on various DFT approaches, the validation parameters according to OECD principles (i.e., the correlation coefficient R2, the predictive squared correlation coefficient q2 and \documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$q_{cv}^{2}$$\end{document}qcv2 from cross-validation) were >0.92, which suggests that the correction model has good stability, robustness and predictive power. Conclusions The correction can be added following DFT calculations. With the obtained molecular descriptors, the NCIs produced by DFT methods can be improved to achieve high-level accuracy. Moreover, only one parameter is introduced into the correction model, which makes it easily applicable. Overall, this work demonstrates that the correction model may be an alternative to the traditional means of correcting for NCIs.A machine learning correction model efficiently improved the accuracy of non-covalent interactions(NCIs) calculated by DFT methods. The application of the correction model is easy and flexible, so it may be an alternative correction means for NCIs by first-principle calculations. ![]() Electronic supplementary material The online version of this article (doi:10.1186/s13321-016-0133-7) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Ting Gao
- School of Computer Science and Information Technology, Northeast Normal University, Changchun, 130117 China
| | - Hongzhi Li
- School of Computer Science and Information Technology, Northeast Normal University, Changchun, 130117 China
| | - Wenze Li
- School of Computer Science and Information Technology, Northeast Normal University, Changchun, 130117 China
| | - Lin Li
- School of Computer Science and Information Technology, Northeast Normal University, Changchun, 130117 China
| | - Chao Fang
- School of Computer Science and Information Technology, Northeast Normal University, Changchun, 130117 China
| | - Hui Li
- School of Computer Science and Information Technology, Northeast Normal University, Changchun, 130117 China
| | - LiHong Hu
- School of Computer Science and Information Technology, Northeast Normal University, Changchun, 130117 China
| | - Yinghua Lu
- School of Computer Science and Information Technology, Northeast Normal University, Changchun, 130117 China ; Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, 130024 China
| | - Zhong-Min Su
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, 130024 China
| |
Collapse
|
16
|
Song F, Zhong Q, Zhao Y. A protophilic solvent-assisted solvothermal approach to Cu-BTC for enhanced CO2
capture. Appl Organomet Chem 2015. [DOI: 10.1002/aoc.3339] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Fujiao Song
- School of Chemical Engineering; Nanjing University of Science and Technology; Nanjing 210094 People's Republic of China
- Nanjing AIREP Environmental Protection Technology Co. Ltd; Nanjing Jiangsu 210091 People's Republic of China
| | - Qin Zhong
- School of Chemical Engineering; Nanjing University of Science and Technology; Nanjing 210094 People's Republic of China
- Nanjing AIREP Environmental Protection Technology Co. Ltd; Nanjing Jiangsu 210091 People's Republic of China
| | - Yunxia Zhao
- School of Chemical Engineering; Nanjing University of Science and Technology; Nanjing 210094 People's Republic of China
| |
Collapse
|
17
|
Singh K, Tiwari MK, Ghosh M, Panda C, Weitz A, Hendrich MP, Dhar BB, Vanka K, Sen Gupta S. Tuning the reactivity of Fe(V)(O) toward C-H bonds at room temperature: effect of water. Inorg Chem 2015; 54:1535-42. [PMID: 25594114 PMCID: PMC4332042 DOI: 10.1021/ic502535f] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Indexed: 11/29/2022]
Abstract
The presence of an Fe(V)(O) species has been postulated as the active intermediate for the oxidation of both C-H and C═C bonds in the Rieske dioxygenase family of enzymes. Understanding the reactivity of these high valent iron-oxo intermediates, especially in an aqueous medium, would provide a better understanding of these enzymatic reaction mechanisms. The formation of an Fe(V)(O) complex at room temperature in an aqueous CH3CN mixture that contains up to 90% water using NaOCl as the oxidant is reported here. The stability of Fe(V)(O) decreases with increasing water concentration. We show that the reactivity of Fe(V)(O) toward the oxidation of C-H bonds, such as those in toluene, can be tuned by varying the amount of water in the H2O/CH3CN mixture. Rate acceleration of up to 60 times is observed for the oxidation of toluene upon increasing the water concentration. The role of water in accelerating the rate of the reaction has been studied using kinetic measurements, isotope labeling experiments, and density functional theory (DFT) calculations. A kinetic isotope effect of ∼13 was observed for the oxidation of toluene and d8-toluene showing that C-H abstraction was involved in the rate-determining step. Activation parameters determined for toluene oxidation in H2O/CH3CN mixtures on the basis of Eyring plots for the rate constants show a gain in enthalpy with a concomitant loss in entropy. This points to the formation of a more-ordered transition state involving water molecules. To further understand the role of water, we performed a careful DFT study, concentrating mostly on the rate-determining hydrogen abstraction step. The DFT-optimized structure of the starting Fe(V)(O) and the transition state indicates that the rate enhancement is due to the transition state's favored stabilization over the reactant due to enhanced hydrogen bonding with water.
Collapse
Affiliation(s)
- Kundan
K. Singh
- Chemical
Engineering Division, CSIR-National Chemical
Laboratory, Pune 411008, India
| | - Mrityunjay k. Tiwari
- Physical
and Materials Chemistry Division, CSIR-National
Chemical Laboratory, Pune 411008, India
| | - Munmun Ghosh
- Chemical
Engineering Division, CSIR-National Chemical
Laboratory, Pune 411008, India
| | - Chakadola Panda
- Chemical
Engineering Division, CSIR-National Chemical
Laboratory, Pune 411008, India
| | - Andrew Weitz
- Department
of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Michael P. Hendrich
- Department
of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Basab B. Dhar
- Chemical
Engineering Division, CSIR-National Chemical
Laboratory, Pune 411008, India
| | - Kumar Vanka
- Physical
and Materials Chemistry Division, CSIR-National
Chemical Laboratory, Pune 411008, India
| | - Sayam Sen Gupta
- Chemical
Engineering Division, CSIR-National Chemical
Laboratory, Pune 411008, India
| |
Collapse
|
18
|
Reddi Y, Sunoj RB. Asymmetric Dual-Catalytic Cascade by Chiral N-Heterocyclic Carbene and Quinuclidine: Mechanism and Origin of Enantioselectivity in Benzofuranone Formation. ACS Catal 2015. [DOI: 10.1021/cs502006x] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Yernaidu Reddi
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Raghavan B. Sunoj
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
19
|
Bello L, Quintero M, Mora AJ, González T, Escalona A, Añez R, Ávila EE, Briceño A. Study of temperature and ligand flexibility effects on coordination polymer formation from cyclobutanetetracarboxylic acid. CrystEngComm 2015. [DOI: 10.1039/c5ce00646e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three novel coordination polymers (CPs) from rctt-H4Cbtc and 4,4’-bpe with Zn and Ni metal nodes have been synthesized. The CP derivates of Zn are an unusual example for the preparation of metastable phases involving temperature dependent and concomitant transformation.
Collapse
Affiliation(s)
- Lizaira Bello
- Laboratorio de Síntesis y Caracterización de Nuevos Materiales
- Centro de Química
- Instituto Venezolano de Investigaciones Científicas
- San Antonio de Los Altos, Venezuela
| | - Marilyn Quintero
- Laboratorio de Síntesis y Caracterización de Nuevos Materiales
- Centro de Química
- Instituto Venezolano de Investigaciones Científicas
- San Antonio de Los Altos, Venezuela
- Laboratorio de Cristalografía
| | - Asiloé J. Mora
- Laboratorio de Cristalografía
- Departamento de Química
- Facultad de Ciencias
- Mérida, Venezuela
| | - Teresa González
- Laboratorio de Síntesis y Caracterización de Nuevos Materiales
- Centro de Química
- Instituto Venezolano de Investigaciones Científicas
- San Antonio de Los Altos, Venezuela
| | - Ana Escalona
- Laboratorio de Síntesis y Caracterización de Nuevos Materiales
- Centro de Química
- Instituto Venezolano de Investigaciones Científicas
- San Antonio de Los Altos, Venezuela
| | - Rafael Añez
- Laboratorio de Química Computacional
- Centro de Química
- Instituto Venezolano de Investigaciones Científicas
- San Antonio de Los Altos, Venezuela
| | - Edward E. Ávila
- Laboratorio de Síntesis y Caracterización de Nuevos Materiales
- Centro de Química
- Instituto Venezolano de Investigaciones Científicas
- San Antonio de Los Altos, Venezuela
| | - Alexander Briceño
- Laboratorio de Síntesis y Caracterización de Nuevos Materiales
- Centro de Química
- Instituto Venezolano de Investigaciones Científicas
- San Antonio de Los Altos, Venezuela
| |
Collapse
|
20
|
Armstrong A, Boto RA, Dingwall P, Contreras-García J, Harvey MJ, Mason NJ, Rzepa HS. The Houk–List transition states for organocatalytic mechanisms revisited. Chem Sci 2014. [DOI: 10.1039/c3sc53416b] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The ten year old Houk–List model for rationalising the origin of stereoselectivity in the organocatalysed intermolecular aldol addition is revisited, using a variety of computational techniques that have been introduced or improved since the original study.
Collapse
Affiliation(s)
- Alan Armstrong
- Department of Chemistry
- Imperial College London
- South Kensington Campus
- London, UK
| | - Roberto A. Boto
- Sorbonne Universités
- UPMC Univ Paris 06
- UMR 7616
- Laboratoire de Chimie Théorique
- Paris, France
| | - Paul Dingwall
- Department of Chemistry
- Imperial College London
- South Kensington Campus
- London, UK
| | - Julia Contreras-García
- Sorbonne Universités
- UPMC Univ Paris 06
- UMR 7616
- Laboratoire de Chimie Théorique
- Paris, France
| | - Matt J. Harvey
- High Performance Computing
- ICT services
- Imperial College London
- UK
| | - Nicholas J. Mason
- Department of Chemistry
- Imperial College London
- South Kensington Campus
- London, UK
| | - Henry S. Rzepa
- Department of Chemistry
- Imperial College London
- South Kensington Campus
- London, UK
| |
Collapse
|
21
|
Chandrasekhar S, Kumar CP, Kumar TP, Haribabu K, Jagadeesh B, Lakshmi JK, Mainkar PS. Peptidomimetic organocatalysts: efficient Michael addition of ketones onto nitroolefins with very low catalyst loading. RSC Adv 2014. [DOI: 10.1039/c4ra04165h] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The syntheses and applications of peptidomimetic triazole-based catalysts are described as efficient organocatalysts in Michael reaction with low loading.
Collapse
Affiliation(s)
- Srivari Chandrasekhar
- Division of Natural Products Chemistry
- CSIR-Indian Institute of Chemical Technology
- Hyderabad, India
| | | | - Togapur Pavan Kumar
- Division of Natural Products Chemistry
- CSIR-Indian Institute of Chemical Technology
- Hyderabad, India
| | - Kothapalli Haribabu
- Division of Natural Products Chemistry
- CSIR-Indian Institute of Chemical Technology
- Hyderabad, India
| | - Bharatam Jagadeesh
- Centre for NMR and Structural Chemistry
- CSIR-Indian Institute of Chemical Technology
- Hyderabad, India
| | - Jerripothula K. Lakshmi
- Centre for NMR and Structural Chemistry
- CSIR-Indian Institute of Chemical Technology
- Hyderabad, India
| | - Prathama S. Mainkar
- Division of Natural Products Chemistry
- CSIR-Indian Institute of Chemical Technology
- Hyderabad, India
| |
Collapse
|
22
|
Role of base assisted proton transfer in N-heterocyclic carbene-catalyzed intermolecular Stetter reaction. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2013.10.116] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
23
|
Liu Y, Zhang D, Bi S, Liu C. Theoretical investigation on Pt(ii)- and Au(i)-mediated cycloisomerizations of propargylic 3-indoleacetate: [3 + 2]- versus [2 + 2]-cycloaddition products. Org Biomol Chem 2013; 11:336-43. [DOI: 10.1039/c2ob26691a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
24
|
Sharma AK, Sunoj RB. Refined Transition-State Models for Proline-Catalyzed Asymmetric Michael Reactions under Basic and Base-Free Conditions. J Org Chem 2012. [DOI: 10.1021/jo3023654] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Akhilesh K. Sharma
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Raghavan B. Sunoj
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
25
|
Sunoj RB, Anand M. Microsolvated transition state models for improved insight into chemical properties and reaction mechanisms. Phys Chem Chem Phys 2012; 14:12715-36. [PMID: 22893252 DOI: 10.1039/c2cp41719g] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Over the years, several methods have been developed to effectively represent the chemical behavior of solutes in solvents. The environmental effects arising due to solvation can generally be achieved either through inclusion of discrete solvent molecules or by inscribing into a cavity in a homogeneous and continuum dielectric medium. In both these approaches of computational origin, the perturbations on the solute induced by the surrounding solvent are at the focus of the problem. While the rigor and method of inclusion of solvent effects vary, such solvation models have found widespread applications, as evident from modern chemical literature. A hybrid method, commonly referred to as cluster-continuum model (CCM), brings together the key advantages of discrete and continuum models. In this perspective, we intend to highlight the latent potential of CCM toward obtaining accurate estimates on a number of properties as well as reactions of contemporary significance. The objective has generally been achieved by choosing illustrative examples from the literature, besides expending efforts to bring out the complementary advantages of CCM as compared to continuum or discrete solvation models. The majority of examples emanate from the prevalent applications of CCM to organic reactions, although a handful of interesting organometallic reactions have also been discussed. In addition, increasingly accurate computations of properties like pK(a) and solvation of ions obtained using the CCM protocol are also presented.
Collapse
Affiliation(s)
- Raghavan B Sunoj
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
| | | |
Collapse
|
26
|
Anand M, Sunoj RB. Role of Explicit Solvents in Palladium(II)-Catalyzed Alkoxylation of Arenes: An Interesting Paradigm for Preferred Outer-Sphere Reductive Elimination over Inner-Sphere Pathway. Organometallics 2012. [DOI: 10.1021/om300681e] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Megha Anand
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Raghavan B. Sunoj
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
27
|
Reddi Y, Sunoj RB. Origin of Stereoselectivity in a Chiral N-Heterocyclic Carbene-Catalyzed Desymmetrization of Substituted Cyclohexyl 1,3-Diketones. Org Lett 2012; 14:2810-3. [DOI: 10.1021/ol301036u] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Yernaidu Reddi
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Raghavan B. Sunoj
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
28
|
Katari M, Rao MN, Rajaraman G, Ghosh P. Computational Insight into a Gold(I) N-Heterocyclic Carbene Mediated Alkyne Hydroamination Reaction. Inorg Chem 2012; 51:5593-604. [DOI: 10.1021/ic2024605] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Madanakrishna Katari
- Department of Chemistry Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India
| | - Mitta Nageswar Rao
- Department of Chemistry Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India
| | - Gopalan Rajaraman
- Department of Chemistry Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India
| | - Prasenjit Ghosh
- Department of Chemistry Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India
| |
Collapse
|
29
|
Rajeev R, Sunoj RB. On the origin of regio- and stereoselectivity in singlet oxygen addition to enecarbamates. J Org Chem 2012; 77:2474-85. [PMID: 22324308 DOI: 10.1021/jo3001707] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The reactions of excited state singlet molecular oxygen ((1)Δ(g),(1)O(2)) continue to witness interesting new developments. In the most recent manifestation, (1)O(2) is tamed to react with enecarbamates in a stereoselective manner, which is remarkable, in view of its inherently high reactivity (Acc. Chem. Res. 2008, 41, 387). Herein, we employed the CAS-MP2(8,7)/6-31G* as well as the CAS-MP2(10,8)/6-31G* computations to unravel the origin of (i) diastereoselectivities in dioxetane or hydroperoxide formation and (ii) regioselectivity leading to a [2 + 2] cycloadduct or an ene product when (1)O(2) reacts with an oxazolidinone tethered 2-phenyl-1-propenyl system. The computed Gibbs free energy profiles for E- and Z-isomers when (1)O(2) approaches through the hindered and nonhindered diastereotopic faces (by virtue of chiral oxazolidinone) of the enecarbamates exhibit distinct differences. In the case of E-isomer, the relative energies of the transition structures responsible for hydroperoxide (ene product) are lower than that for dioxetane formation. On the other hand, the ene pathway is predicted to involve higher barriers as compared to the corresponding dioxetane pathway for Z-isomer. The energy difference between the rate-determining diastereomeric transition structures involved in the most favored ene reaction for E-enecarbamate suggests high diastereoselectivity. In contrast, the corresponding energy difference for Z-enecarbamate in the ene pathway is found to be diminishingly close, implying low diastereoselectivity. However, the dioxetane formation from Z-enecarbamate is predicted to exhibit high diastereoselectivity. The application of activation strain model as well as the differences in stereoelectronic effects in the stereocontrolling transition structures is found to be effective toward rationalizing the origin of selectivities reported herein. These predictions are found to be in excellent agreement with the experimental observations.
Collapse
Affiliation(s)
- Ramanan Rajeev
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | | |
Collapse
|
30
|
Yang H, Wong MW. (S)-Proline-catalyzed nitro-Michael reactions: towards a better understanding of the catalytic mechanism and enantioselectivity. Org Biomol Chem 2012; 10:3229-35. [DOI: 10.1039/c2ob06993h] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|
31
|
Anand M, Sunoj RB. Palladium(II)-catalyzed direct alkoxylation of arenes: evidence for solvent-assisted concerted metalation deprotonation. Org Lett 2011; 13:4802-5. [PMID: 21859083 DOI: 10.1021/ol201830r] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Density functional theory investigations on the mechanism of palladium acetate catalyzed direct alkoxylation of N-methoxybenzamide in methanol reveal that the key steps involve solvent-assisted N-H as well as C-H bond activations. The transition state for the critical palladium-carbon bond formation through a concerted metalation deprotonation (CMD) process leading to a palladacycle intermediate has been found to be more stable in the methanol-assisted pathway as compared to an unassisted route.
Collapse
Affiliation(s)
- Megha Anand
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | | |
Collapse
|
32
|
Cheong PHY, Legault CY, Um JM, Çelebi-Ölçüm N, Houk KN. Quantum mechanical investigations of organocatalysis: mechanisms, reactivities, and selectivities. Chem Rev 2011; 111:5042-137. [PMID: 21707120 PMCID: PMC3154597 DOI: 10.1021/cr100212h] [Citation(s) in RCA: 425] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Paul Ha-Yeon Cheong
- Oregon State University, Department of Chemistry, 153 Gilbert Hall, Corvallis, OR 97331-4003 USA
| | - Claude Y. Legault
- University of Sherbrooke, Department of Chemistry, 2500 boul. de l’Université, local D1-3029, Sherbrooke (Québec) J1K 2R1 CANADA
| | - Joann M. Um
- University of California Los Angeles, Department of Chemistry and Biochemistry, 607 Charles E. Young Drive East, Los Angeles, CA 90095-1569 USA
| | - Nihan Çelebi-Ölçüm
- University of California Los Angeles, Department of Chemistry and Biochemistry, 607 Charles E. Young Drive East, Los Angeles, CA 90095-1569 USA
| | - K. N. Houk
- University of California Los Angeles, Department of Chemistry and Biochemistry, 607 Charles E. Young Drive East, Los Angeles, CA 90095-1569 USA
| |
Collapse
|
33
|
Jentzsch KI, Min T, Etcheson JI, Fettinger JC, Franz AK. Silyl Fluoride Electrophiles for the Enantioselective Synthesis of Silylated Pyrrolidine Catalysts. J Org Chem 2011; 76:7065-75. [DOI: 10.1021/jo200991q] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kaleb I. Jentzsch
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
| | - Taewoo Min
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
| | - Jennifer I. Etcheson
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
| | - James C. Fettinger
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
| | - Annaliese K. Franz
- Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, United States
| |
Collapse
|
34
|
Verma P, Patni PA, Sunoj RB. Mechanistic Insights on N-Heterocyclic Carbene-Catalyzed Annulations: The Role of Base-Assisted Proton Transfers. J Org Chem 2011; 76:5606-13. [DOI: 10.1021/jo200560t] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
35
|
|
36
|
Janardanan D, Sunoj RB. Chemo-, regio-, and diastereoselectivity preferences in the reaction of a sulfur ylide with a dienal and an enone. Org Biomol Chem 2011; 9:1642-52. [PMID: 21253652 DOI: 10.1039/c0ob00675k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mechanistic insights into an interesting class of reaction between sulfur ylides with (i) a dienal, and (ii) an enone, obtained by using density functional theory, is reported. The kinetic and thermodynamic factors responsible for chemo-, regio-, and diastereoselectivities are established by identifying all key transition states and intermediates along the reaction pathway for 1,2-, 1,4-, and 1,6- modes of attack of dimethylsulfonium benzylide to 5-phenylpenta-2,4-dienal. The reaction profiles for 1,2- and 1,4- modes of addition are also evaluated for the reaction between dimethylsulfonium benzylide and pent-3-en-2-one. Our results show that the final outcome of the reaction with both these substrates would be decided by the interplay between kinetic and thermodynamic factors. It is found that the addition of a semi-stabilized ylide to conjugated carbonyl compounds prefers to proceed through a 1,4- (conjugate) pathway under thermodynamic conditions, which is in accordance with the available experimental reports. However, the formation of epoxides via a 1,2- (direct) addition pathway is computed to be equally competitive, which could be the favored pathway under kinetic conditions. Even though the lower barrier for the initial addition step is kinetically advantageous for the direct (or 1,2-) addition pathway, the higher energy of the betaine intermediates--as well as the reversibility of the accompanying elementary step--may disfavor product formation in this route. Thus, high diastereoselectivity in favor of 2,3-trans cyclopropanecarbaldehyde is predicted in the case of the dienal, using the most favored conjugate addition (1,4-addition) pathway. Along similar lines, ylide addition to the enone is identified to exhibit a preference toward conjugate addition over direct (1,2-) addition. The importance of transition state analysis in delineating the controlling factors towards product distribution and diastereoselectivity is established.
Collapse
Affiliation(s)
- Deepa Janardanan
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | | |
Collapse
|
37
|
Sharma AK, Sunoj RB. Stereocontrol in proline-catalyzed asymmetric amination: a comparative assessment of the role of enamine carboxylic acid and enamine carboxylate. Chem Commun (Camb) 2011; 47:5759-61. [DOI: 10.1039/c1cc11063b] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
38
|
|
39
|
Sharma AK, Sunoj RB. Enamine versus oxazolidinone: what controls stereoselectivity in proline-catalyzed asymmetric aldol reactions? Angew Chem Int Ed Engl 2010; 49:6373-7. [PMID: 20665610 DOI: 10.1002/anie.201001588] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Akhilesh K Sharma
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | | |
Collapse
|
40
|
Patil MP, Sharma AK, Sunoj RB. Importance of the Nature of α-Substituents in Pyrrolidine Organocatalysts in Asymmetric Michael Additions. J Org Chem 2010; 75:7310-21. [DOI: 10.1021/jo101592b] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mahendra P. Patil
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Akhilesh K. Sharma
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Raghavan B. Sunoj
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| |
Collapse
|
41
|
Sharma A, Sunoj R. Enamine versus Oxazolidinone: What Controls Stereoselectivity in Proline-Catalyzed Asymmetric Aldol Reactions? Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201001588] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
42
|
Computational investigations of the stereoselectivities of proline-related catalysts for aldol reactions. ACTA ACUST UNITED AC 2010; 324:31-38. [PMID: 20634993 DOI: 10.1016/j.molcata.2010.03.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Computational investigation of the aldol reaction of benzaldehyde with acetone catalyzed by various proline derivatives and 2-azetidine carboxylic acid reveal the origins of stereoselectivities of these reactions. Structural differences between catalysts and transition states were analyzed with density functional theory geometries in order to establish the key factors that will help in the design of new catalysts.
Collapse
|
43
|
Roy D, Patel C, Sunoj RB. Mechanistic insights and the role of cocatalysts in Aza-Morita-Baylis-hillman and Morita-Baylis-Hillman reactions. J Org Chem 2010; 74:6936-43. [PMID: 19697897 DOI: 10.1021/jo900622x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The mechanism of the trimethylamine or trimethylphosphine catalyzed aza-Morita-Baylis-Hillman (MBH) reaction between acrolein and mesyl imine is investigated by using ab initio and density functional methods. All key transition states are located at the CBS-4M as well as at the mPW1K/6-31+G** levels of theories. To account for the experimentally known rate enhancements through the use of polar protic cocatalysts, transition state models with explicit cocatalysts are considered. Inclusion of polar protic cocatalysts is found to have a profound influence in decreasing the activation barriers associated with the key elementary steps. The protic cocatalysts such as water, methanol, and formic acid are identified as effective in promoting a relay proton transfer. Interestingly, the efficiency of the relay mechanism results in relatively better stabilization of the proton transfer transition state as compared to the addition of enolate to the electrophile (C-C bond formation). The cocatalyst bound models suggest that the proton transfer could become the rate-determining step in the aza-MBH reaction under polar protic conditions. A comparison of the aza-MBH reaction with the analogous MBH reaction is also attempted to bring out the subtle differences between these two reactions. Enhanced kinetic advantages arising from the nature of the activated electrophile are noticed for the aza-MBH reaction. The difference in the relative energies between the transition states for the proton transfer and the C-C bond formation steps with bound cocatalyst(s) is found to be more pronounced in the aza-MBH reaction. In general, the reported results underscore the importance of considering explicit solvents/cocatalysts in order to account for the likely role of the specific interactions between reactants and solvents/cocatalysts.
Collapse
Affiliation(s)
- Dipankar Roy
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | | | | |
Collapse
|
44
|
Patil MP, Sunoj RB. On the relative preference of enamine/iminium pathways in an organocatalytic Michael addition reaction. Chem Asian J 2009; 4:714-24. [PMID: 19353592 DOI: 10.1002/asia.200800351] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The mechanism of the organocatalyzed Michael addition between propanal and methyl vinyl ketone is investigated using the density functional and ab intio methods. Different modes of substrate activation offered by a secondary amine (pyrrolidine) organocatalyst are reported. The electrophilic activation of enone (P-I) through the formation of an iminium ion, and nucleophilic activation of propanal (P-II) in the form of enamine have been examined by identifying the corresponding transition states. The kinetic preference for the formation of key intermediates is established in an effort to identify the competing pathways associated with the title reaction. A comparison of barriers associated with different pathways as well as intermediate formation allows us to provide a suitable mechanistic rationale for Michael addition reactions catalyzed by a secondary amine. The overall barriers for the C-C bond formation pathways involving enol or iminium intermediates are identified as higher than the enamine pathway. Additionally, the generation of iminium is found to be less favored as compared to enamine formation. The effect of co-catalyst/protic solvent on the energetics of the overall reaction is also studied using the cluster continuum approach. Significant reduction in the activation energies for each step of the reaction is predicted for the solvent-assisted models. The co-catalyst assisted addition of propanal-enamine to methyl vinyl ketone is identified as the most preferred pathway (P-IV) for the Michael addition reaction. The results are in concurrence with the available experimental reports on the rate acceleration by the use of a co-catalyst in this reaction.
Collapse
Affiliation(s)
- Mahendra P Patil
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | | |
Collapse
|
45
|
Laars M, Ausmees K, Uudsemaa M, Tamm T, Kanger T, Lopp M. Enantioselective Organocatalytic Michael Addition of Aldehydes to β-Nitrostyrenes. J Org Chem 2009; 74:3772-5. [DOI: 10.1021/jo900322h] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marju Laars
- Department of Chemistry, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Kerti Ausmees
- Department of Chemistry, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Merle Uudsemaa
- Department of Chemistry, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Toomas Tamm
- Department of Chemistry, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Tõnis Kanger
- Department of Chemistry, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| | - Margus Lopp
- Department of Chemistry, Tallinn University of Technology, Akadeemia tee 15, 12618 Tallinn, Estonia
| |
Collapse
|
46
|
Roy D, Sunoj RB. Water catalysis in the Morita-Baylis-Hillman reaction: a mechanistic perspective. Chemistry 2008; 14:10530-4. [PMID: 18988243 DOI: 10.1002/chem.200801822] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Dipankar Roy
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
| | | |
Collapse
|