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Trudel V, Brien C, Tan J, Yudin AK. Towards depeptidized aminoboronic acid derivatives through the use of borylated iminium ions. Chem Commun (Camb) 2022; 58:5033-5036. [PMID: 35377379 DOI: 10.1039/d2cc00659f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we use α-boryl iminium intermediates to access progressively depeptidized branched β-aminoboronic acids that are functionalized with biologically relevant heterocycles. We investigate the interaction of these novel compounds with carbohydrates under physiological conditions and demonstrate their potential as synthetic building blocks.
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Affiliation(s)
- Vincent Trudel
- Davenport Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON, M5S 3H6, Canada.
| | - Chelsey Brien
- Davenport Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON, M5S 3H6, Canada.
| | - Joanne Tan
- Davenport Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON, M5S 3H6, Canada.
| | - Andrei K Yudin
- Davenport Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON, M5S 3H6, Canada.
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2
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Wysokinski R, Zierkiewicz W, Michalczyk M, Scheiner S. Competition between Intra and Intermolecular Pnicogen Bonds. Complexes between Naphthalene Derivatives and Neutral or Anionic Bases. Chemphyschem 2022; 23:e202200173. [PMID: 35385595 DOI: 10.1002/cphc.202200173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/04/2022] [Indexed: 11/09/2022]
Abstract
The PnF 2 (Pn=P,As,Sb,Bi) on a naphthalene scaffold can engage in an internal pnicogen Pn···N bond (PnB) with a NH 2 group placed close to it on the adjoining ring. An approaching neutral NH 3 molecule can engage in a second PnB with the central Pn, which tends to weaken the intramolecular bond. The presence of the latter in turn weakens the intermolecular PnB with respect to that formed in its absence. Replacement of the external NH 3 by a CN - anion causes a fundamental change in the bonding pattern, producing a fourth covalent bond with Pn, which rearranges into a trigonal bipyramidal motif. This addition disrupts the internal Pn···N pnicogen bond, recasting the PnF 2 ···NH 2 interaction into a NH···F H-bond.
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Affiliation(s)
- Rafal Wysokinski
- Wroclaw University of Science and Technology, Faculty of Chemistry, Wyb. Wyspiańskiego 27, 50-370, Wroclaw, POLAND
| | - Wiktor Zierkiewicz
- Wroclaw University of Science and Technology: Politechnika Wroclawska, Chemistry Department, POLAND
| | - Mariusz Michalczyk
- Wroclaw University of Science and Technology: Politechnika Wroclawska, Chemistry Department, POLAND
| | - Steve Scheiner
- Utah State University, Department of Chemistry and Biochemistry, UNITED STATES
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3
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Du Y, Sari O, Erdem SS, Whiting A. A Bifunctional B,N‐Based Asymmetric Catalytic Nitrostyrene‐
Michael
Addition Acting through a 10‐Membered Ring Cyclic Transition State. Helv Chim Acta 2021. [DOI: 10.1002/hlca.202100199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Yihao Du
- Department of Chemistry Durham University Science Laboratories South Road Durham DH1 3QZ United Kingdom
| | - Ozlem Sari
- Network Technologies Department TÜBİTAK ULAKBİM TR-06800 Ankara Turkey
| | - Safiye S. Erdem
- Chemistry Department Faculty of Arts and Sciences Marmara University TR-34722 Goztepe, Istanbul Turkey
| | - Andrew Whiting
- Department of Chemistry Durham University Science Laboratories South Road Durham DH1 3QZ United Kingdom
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4
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Abstract
Among the renewable energy sources is biodiesel. This fuel is usually produced by catalytic transesterification of vegetable oils and animal fats under heating and pressure. Brown grease is a mixture of oils, fats, solids and detergents from food industry wastes that is captured in grease traps. Brown grease is classified as waste and must be treated and disposed of appropriately. It contains oils and fats that can be converted into biodiesel. However, the high concentration of free fatty acids in brown grease does not enable the use of conventional biodiesel production schemes. This study proposes a new scheme for biodiesel production from brown grease. In addition, conditions for the effective separation of a fat phase from brown grease were tested, and the composition of a fatty phase was determined for several grease traps. Esterification and transesterification of brown grease lipids were carried out with methanol, where the Lewis acids BF3 and AlCl3 were used as catalysts and the reaction was activated by ultrasound. The results show that biodiesel can be obtained from brown grease by esterification and transesterification within several minutes under ultrasonic activation at room temperature. These results open prospects for the development of efficient, low-cost and environmentally friendly biodiesel production.
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5
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Zierkiewicz W, Michalczyk M, Scheiner S. Competition between Intra and Intermolecular Triel Bonds. Complexes between Naphthalene Derivatives and Neutral or Anionic Lewis Bases. Molecules 2020; 25:E635. [PMID: 32024163 PMCID: PMC7037318 DOI: 10.3390/molecules25030635] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 01/29/2020] [Accepted: 01/31/2020] [Indexed: 12/12/2022] Open
Abstract
: A TrF2 group (Tr = B, Al, Ga, In, Tl) is placed on one of the α positions of naphthalene, and its ability to engage in a triel bond (TrB) with a weak (NCH) and strong (NC-) nucleophile is assessed by ab initio calculations. As a competitor, an NH2 group is placed on the neighboring Cα, from which point it forms an intramolecular TrB with the TrF2 group. The latter internal TrB reduces the intensity of the π-hole on the Tr atom, decreasing its ability to engage in a second external TrB. The intermolecular TrB is weakened by a factor of about two for the smaller Tr atoms but is less severe for the larger Tl. The external TrB can be quite strong nonetheless; it varies from a minimum of 8 kcal/mol for the weak NCH base, up to as much as 70 kcal/mol for CN-. Likewise, the appearance of an external TrB to a strong base like CN- lessens the ability of the Tr to engage in an internal TrB, to the point where such an intramolecular TrB becomes questionable.
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Affiliation(s)
- Wiktor Zierkiewicz
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland;
| | - Mariusz Michalczyk
- Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland;
| | - Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322-0300, USA
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6
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De Carvalho GSG, Granato ÁS, De Castro PP, Amarante GW. Recent Contributions of Nuclear Magnetic Resonance in Organocatalysis Mechanism Elucidation. CURRENT ORGANOCATALYSIS 2019. [DOI: 10.2174/2213337206666190328210907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background:
Nuclear Magnetic Resonance (NMR) is one of the most employed techniques
in structural elucidation of organic compounds. In addition to its use in structural characterization,
it has been widely employed in the investigation of reaction mechanisms, especially those involving
catalysis.
Objective:
In this review, we aim to provide recent examples of the interface of NMR and organocatalysis
reaction mechanism.
Methods:
Selected examples of different approaches for mechanism elucidation will be presented,
such as isotopic effect, catalyst labelling and online reaction monitoring. A discussion involving the
use of solid-state NMR will also be disclosed.
Conclusion:
NMR consists of a non-destructive technique, extremely useful in the real-time identification
of intermediates in crude reaction mixtures. With the advent of two-dimensional experiments
and high field NMR spectrometers, the reports of studies involving mechanistic elucidation were
greatly enhanced. In this context, nowadays NMR appears as a powerful tool for the comprehension
of reaction mechanisms, including the possibility of the proposal of unknown reaction mechanisms
within organocatalysis.
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Affiliation(s)
| | - Álisson Silva Granato
- Department of Chemistry, Federal University of Juiz de Fora, Campus Martelos, Juiz de Fora, Minas Gerais 36036900, Brazil
| | - Pedro Pôssa De Castro
- Department of Chemistry, Federal University of Juiz de Fora, Campus Martelos, Juiz de Fora, Minas Gerais 36036900, Brazil
| | - Giovanni Wilson Amarante
- Department of Chemistry, Federal University of Juiz de Fora, Campus Martelos, Juiz de Fora, Minas Gerais 36036900, Brazil
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7
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Cozzi PG, Gualandi A, Potenti S, Calogero F, Rodeghiero G. Asymmetric Reactions Enabled by Cooperative Enantioselective Amino- and Lewis Acid Catalysis. Top Curr Chem (Cham) 2019; 378:1. [PMID: 31761979 DOI: 10.1007/s41061-019-0261-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 10/22/2019] [Indexed: 01/04/2023]
Abstract
Organocatalysis-the branch of catalysis featuring small organic molecules as the catalysts-has, in the last decade, become of central importance in the field of asymmetric catalysis, so much that it is now comparable to metal catalysis and biocatalysis. Organocatalysis is rationalized and classified by a number of so-called activation modes, based on the formation of a covalent or not-covalent intermediate between the organocatalyst and the organic substrate. Among all the organocatalytic activation modes, enamine and iminium catalysis are widely used for the practical preparation of valuable products and intermediates, both in academic and industrial contexts. In both cases, chiral amines are employed as catalysts. Enamine activation mode is generally employed in the reaction with electrophiles, while nucleophiles require the iminium activation mode. Commonly, in both modes, the reaction occurs through well-organized transitions states. A large variety of partners can react with enamines and iminium ions, due to their sufficient nucleophilicity and electrophilicity, respectively. However, despite the success, organocatalysis still suffers from narrow scopes and applications. Multicatalysis is a possible solution for these drawbacks because the two different catalysts can synergistically activate the substrates, with a simultaneous activation of the two different reaction partners. In particular, in this review we will summarize the reported processes featuring Lewis acid catalysis and organocatalytic activation modes synergically acting and not interfering with each other. We will focus our attention on the description of processes in which good results cannot be achieved independently by organocatalysis or Lewis acid catalysis. In these examples of cooperative dual catalysis, a number of new organic transformations have been developed. The review will focus on the possible strategies, the choice of the Lewis acid and the catalytic cycles involved in the effective reported combination. Additionally, some important key points regarding the rationale for the effective combinations will be also included. π-Activation of organic substrates by Lewis acids, via formation of electrophilic intermediates, and their reaction with enamines will be also discussed in this review.
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Affiliation(s)
- Pier Giorgio Cozzi
- Dipartimento di Chimica "G. Ciamician", Alma Mater Studiorum, Università di Bologna, Via Selmi 2, Bologna, Italy.
| | - Andrea Gualandi
- Dipartimento di Chimica "G. Ciamician", Alma Mater Studiorum, Università di Bologna, Via Selmi 2, Bologna, Italy
| | - Simone Potenti
- Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126, Pisa, Italy
| | - Francesco Calogero
- Dipartimento di Chimica "G. Ciamician", Alma Mater Studiorum, Università di Bologna, Via Selmi 2, Bologna, Italy
| | - Giacomo Rodeghiero
- Dipartimento di Chimica "G. Ciamician", Alma Mater Studiorum, Università di Bologna, Via Selmi 2, Bologna, Italy
- Cyanagen Srl, Via Stradelli Guelfi 40/C, 40138, Bologna, Italy
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8
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Dulger H, Sari O, Demirel N, Erdem SS. Computational Insight Into the Enantioselectivity of Homoboroproline Catalyzed Asymmetric Aldol Reaction. ChemistrySelect 2019. [DOI: 10.1002/slct.201901737] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Habibe Dulger
- Department of Chemistry, Faculty of Arts and SciencesMarmara University, Goztepe Campus 34722 Istanbul Turkey
- Department of ChemistryKirsehir Ahi Evran University 40100 Kirsehir Turkey
| | - Ozlem Sari
- Department of ChemistryKirsehir Ahi Evran University 40100 Kirsehir Turkey
| | - Nadir Demirel
- Department of ChemistryKirsehir Ahi Evran University 40100 Kirsehir Turkey
| | - Safiye S. Erdem
- Department of Chemistry, Faculty of Arts and SciencesMarmara University, Goztepe Campus 34722 Istanbul Turkey
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9
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Abstract
Although boronic acids are recognized primarily for their utility as reagents in transition metal-catalyzed transformations, other applications are emerging, including their use as reaction catalysts.
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Affiliation(s)
- Dennis G. Hall
- Department of Chemistry
- University of Alberta
- Edmonton
- Canada
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10
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11
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Gumus OY, Ozkan S, Unal HI. A Comparative Study on Electrokinetic Properties of Boronic Acid Derivative Polymers in Aqueous and Nonaqueous Media. MACROMOL CHEM PHYS 2016. [DOI: 10.1002/macp.201500524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Omer Yunus Gumus
- Department of Chemistry; Faculty of Arts and Science; Nevsehir Haci Bektas Veli University; Nevsehir 50300 Turkey
| | - Seyma Ozkan
- Smart Materials Research Laboratory; Department of Chemistry; Faculty of Science; University of Gazi; Ankara 06560 Turkey
| | - Halil Ibrahim Unal
- Smart Materials Research Laboratory; Department of Chemistry; Faculty of Science; University of Gazi; Ankara 06560 Turkey
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12
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Pla D, Sadek O, Cadet S, Mestre-Voegtlé B, Gras E. Naphthylaminoborane: from structural switches to frustrated Lewis pair reactivity. Dalton Trans 2015; 44:18340-6. [PMID: 26352756 DOI: 10.1039/c5dt02659h] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of naphthyl-bridged amino-borane derivatives, namely 1-(dimethylamino)-8-naphthylboranes (1, 3, 5, 7) and 5-(dimethylamino)-6-acenaphthylboranes (2, 4, 6, 8, 10, 11), differing in the steric and electronic properties of the boryl moiety, have been synthesized and fully characterized by spectroscopic and crystallographic means. Structural X-ray analysis of the peri-atom displacement and ring torsion angles served to experimentally assess the presence and magnitude of the B-N interactions. The reversible quaternarization of nitrogen has been explored and was found to provide an efficient switch corresponding to different molecular organizations. The electronic characteristics of the nature of B-N interactions were further studied by Natural Bonding Orbital analysis derived from the theoretically calculated electron densities. This real-space bonding indicator discriminates the bonding B-N contact in 5 from the nonbonding in 8, which correlates with the flexibility of the naphthyl scaffold to respond to the Lewis acidity of boron allowing shorter peri interactions. Whereas, the steric shielding imposed by the two mesityl groups, and/or the rigidity of the acenaphthene framework disrupt B-N interaction. Thus, this communication reports on the modulation of the B-N bonding continuum by means of structural tuning leading to a molecular switch, as well as its implications towards revealing FLP reactivities through the isolation of intermediates of a stepwise mechanism.
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Affiliation(s)
- Daniel Pla
- Laboratoire de Chimie de Coordination, Centre National de la Recherche Scientifique UPR 8241, 205, Route de Narbonne, F-31077 Toulouse, France.
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13
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Chronopoulos DD, Kokotos CG, Karousis N, Kokotos G, Tagmatarchis N. Functionalized multi-walled carbon nanotubes in an aldol reaction. NANOSCALE 2015; 7:2750-2757. [PMID: 25585101 DOI: 10.1039/c4nr06543c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The covalent functionalization of multi-walled carbon nanotubes (MWCNTs) with a proline-based derivative is reported. Initially, MWCNTs were oxidized in order to introduce a large number of carboxylic units on their tips followed by N-tert-butoxycarbonyl-2,2'(ethylenedioxy)bis-(ethylamine) conjugation through an amide bond. Then, a proline derivative bearing a carboxylic terminal moiety at the 4-position was coupled furnishing proline-modified MWCNTs. This new hybrid material was fully characterized by spectroscopic and microscopy means and its catalytic activity in the asymmetric aldol reaction between acetone and 4-nitrobenzaldehyde was evaluated for the first time, showing to proceed almost quantitatively in aqueous media. Furthermore, several amino-modified MWCNTs were prepared and examined in the particular aldol reaction. These new hybrid materials exhibited an enhanced catalytic activity in water, contrasting with the pristine MWCNTs as well as the parent organic molecule, which failed to catalyze the reaction efficiently. Furthermore, the modified MWCNTs proved to catalyze the aldol reaction even after three repetitive cycles. Overall, a green approach for the aldol reaction is presented, where water can be employed as the solvent and modified MWCNTs can be used as catalysts, which can be successfully recovered and reused, while their catalytic activity is retained.
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Affiliation(s)
- D D Chronopoulos
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens 116 35, Greece.
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14
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Gualandi A, Mengozzi L, Wilson CM, Cozzi PG. Synergy, Compatibility, and Innovation: Merging Lewis Acids with Stereoselective Enamine Catalysis. Chem Asian J 2014; 9:984-95. [DOI: 10.1002/asia.201301549] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Indexed: 01/03/2023]
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15
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Batsanov AS, Georgiou I, Girling PR, Pommier L, Shen HC, Whiting A. Asymmetric Synthesis and Application of Homologous Pyrroline-2-alkylboronic Acids: Identification of the B-N Distance for Eliciting Bifunctional Catalysis of an Asymmetric Aldol Reaction. ASIAN J ORG CHEM 2013. [DOI: 10.1002/ajoc.201300127] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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16
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Georgiou I, Whiting A. Enantioselective Synthesis of (R)-Homoboroproline from (S)-Proline Using a Borylation Approach. European J Org Chem 2012. [DOI: 10.1002/ejoc.201200652] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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