Mass Spectrometry: Insightful Window for Organic Chemistry
Received Date: Sep 25, 2012 / Accepted Date: Sep 26, 2012 / Published Date: Sep 30, 2012
Just recently, Vijaya Krishna Varanasi represented the advantages of open access journals , thus we want to share some ideas based on our mass spectrometric researches for organic chemistry in “Organic Chemistry: Current Research”. Mass spectrometer, as a tool of weighing the ions, is applied widely in natural science. With massive progress in ionization techniques and mass analysers recently, modern mass spectrum characterized by sensitivity, speed, specificity and stoichiometry , opens an insightful window for deepening the understanding of the organic chemistry. As the key point in understanding the mechanisms of organic reactions, the identification of reactive intermediates is nearly always a challenging task because they are short-lived and hardly separated from other related complexes. Electrospray ionization (ESI) is a method of transferring real-world ions from solution to the gas phase . Because reactive species are almost infinitely stable due to high-vacuum conditions in the gas phase  and active species with a charge can be probed selectively, ESI-MS has become increasingly popular in characterization of active intermediates especially combined with tandem mass spectrometric (MSn) methods [4-9].
Since Aliprantis et al. studied the catalytic intermediates in the Suzuki reaction by ESI-MS in 1994 , ESI-MS has been widely used in studies of the intermediates and mechanisms of metal-catalyzed reactions. We systematically studied the Ru-olefin metathesis catalysts [11,12], the Ru-catalyzed olefin metathesis reactions [13,14] and the CH3CN-assisted decomposition reaction of the 1st Grubbs catalyst . These work made those proposed mechanisms be proved to some extent and will help to optimize and develop the reaction conditions and application scope of catalysts. Other than mechanisms of metal-catalyzed reactions, ESI-MS is also applied in studies on the mechanism of organocatalysis reactions [16,17] and free radical reactions [18-20]. We have studied the interaction of radical traps (Tempo and Dmpo) and radicals produced in the electrophilic fluorination of olefins and Selectfluor by ESI-MS, which provides evidence for presence of a single-electron transfer mechanism in electrophilic fluorination [21,22]. The limitation of ESI-MS method is that the species have to be charged. However, possible omission of important neutral reaction intermediates can be circumvented by the introduction of an easily ionizable group to a remote position of the catalyst or the substrate . Furthermore, combined with microreactor, on-line ESI-MS have proven to be particularly effective in the investigation of systems involving relatively unstable products, which would not survive the normal handling, quenching, and storage practices typical of off-line strategies [5,24]. Thus, ESI-MS will applied in understanding the mechanisms of more organic reactions in the future.
The reaction mechanisms sometimes can be better revealed in the subtle details in the gas phase for which are always complicated by hydrogen bond and solvation effect in the condensed phase . However, gas phase reactions are difficult to study in the normal experiment conditions. The modern mass spectrometer, as a complete chemical laboratory, provides an ideal tool . Name reactions are foundation for organic chemistry and similar reactions could also occur in gas phase. Till now, two name reactions “McLafferty rearrangement”  and “Eberlin reaction”  occurred in mass spectrometry. Several interesting gas phase reactions have also been investigated by our group: like the Smiles and related rearrangements of aromatic systems [29-31], sulfonyl-sulfinate rearrangement [32,33], retro-Michael type fragmentation reactions , Clasien rearrangement reaction  and Favorskii rearrangement . We also used tandem mass spectrometry to predict chemical transformations of 2-pyrimidinyloxy-N-arylbenzyl amine derivatives in solution based on study of intrinsic properties of reactions in gas phase before . “Gas phase firstly and then condensed phase”, this idea puts insight into quick discovery of complexes’ potential reactive centers.
Learning the world via mass, mass spectrum has great advantages in understanding the mechanisms of organic reactions and the gas-phase reactions . Combined with contemporary new technologies, we are confident that mass spectrum will give more surprises to the organic chemists. Significant challenges still remain to be overcome in study of mechanisms in both gas phase and solution organic reactions by mass spectrometry and related technologies. The journal “Organic chemistry: Current Research” from OMICS Publishing Group would provide more opportunities to present key issues in advances in the use of mass spectrometric methods to solve the organic chemistry problems.
- Vijaya Krishna V (2012) Molecularly imprinted polymers: the way forward. Organic Chem Current Res 1: e101.
- McLafferty FW, Fridriksson EK, Horn DM, Lewis MA, Zubarev RA (1999) Techview: biochemistry. Biomolecule mass spectrometry. Science 284: 1289-1290.
- Yamashita M, Fenn JB (1984) Electrospray ion source. Another variation on the free-jet theme. J Phys Chem 88: 4451-4459.
- Plattner DA (2001) Electrospray mass spectrometry beyond analytical chemistry: studies of organometallic catalysis in the gas phase. Int J Mass Spectrom 207: 125-144.
- Santos LS, Knaack L, Metzger JO (2005) Investigation of chemical reactions in solution using API-MS. Int J Mass Spectrom 246: 84-104
- Eberlin MN (2007) Electrospray ionization mass spectrometry: a major tool to investigate reaction mechanisms in both solution and the gas phase. Eur J Mass Spectrom (Chichester, Eng) 13: 19-28.
- Zhao ZX, Wang HY, Guo YL (2011) Studies of heterogeneous/homogeneous ion-molecule reactions by ambient ionization mass spectrometry. Curr Org Chem 15: 3734-3749.
- SchrÃ¶der D (2012) Applications of electrospray ionization mass spectrometry in mechanistic studies and catalysis research. Acc Chem Res 45: 1521-1532.
- O'Hair RAJ (2006) The 3D quadrupole ion trap mass spectrometer as a complete chemical laboratory for fundamental gas-phase studies of metal mediated chemistry. Chem Commun 14: 1469-1481.
- Aliprantis AO, Canary JW (1994) Observation of catalytic intermediates in the Suzuki reaction by electrospray mass spectrometry. J Am Chem Soc 116: 6985–6986.
- Wang HY, Fabbretti F, Metzger JO (2008) ESI-MS Study on first generation Ruthenium olefin metathesis catalysts in solution: direct detection of the catalytically active 14-electron ruthenium intermediate. Organometallics 27: 2761-2766.
- Wang HY, Yim WL, Kluner T, Metzger JO (2009) ESIMS studies and calculations on alkali-metal adduct ions of ruthenium olefin metathesis catalysts and their catalytic activity in metathesis reactions. Chemistry 15: 10948-10959.
- Zhu W, Wang HY, Guo YL (2012) Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analyses of Grubbs catalysts and ferrocene derivatives using sulfur as matrix. J Mass Spectrom 47: 352-354.
- Wang H.Y, Yim WL, Guo YL, Metzger JO (2012) ESI-MS studies and calculations on second-generation Grubbs and Hoveyda-Grubbs ruthenium olefin metathesis catalysts. Organometallics 31: 1627-1634.
- Zhao ZX, Wang HY, Guo YL (2011) Studies on CH3CN-assisted decomposition of 1st Grubbs catalyst by electrospray ionization tandem mass spectrometry. Rapid Commun Mass Spectrom 25: 3401-3410.
- Santos LS, Pavam CH, Almeida WP, Coelho F, Eberlin MN (2004) Probing the mechanism of the Baylis-Hillman reaction by electrospray ionization mass and tandem mass spectrometry. Angew Chem Int Ed Engl 43: 4330-4333.
- Wang HY, Zhou J, Guo YL (2012) Study on the reactive transient Î±-Î»3-iodanyl-acetophenone complex in the iodine(III)/PhI(I) catalytic cycle of iodobenzene-catalyzed Î±-acetoxylation reaction of acetophenone by electrospray ionization tandem mass spectrometry. Rapid Commun Mass Spectrom 26: 616-620.
- Marquez C, Metzger JO (2006) ESI-MS study on the aldol reaction catalyzed by L-proline. Chem Commun 14: 1539–1541.
- Gaikwad NW, Rogan EG, Cavalieri EL (2007) Evidence from ESI-MS for NQO1-catalyzed reduction of estrogen ortho-quinones. Free Radic Biol Med 43: 1289-1298.
- Marquez CA, Wang H, Fabbretti F, Metzger JO (2008) Electron-transfer-catalyzed dimerization of trans-anethole: detection of the distonic tetramethylene radical cation intermediate by extractive electrospray ionization mass spectrometry. J Am Chem Soc 130: 17208-17209.
- Zhang X, Liao Y, Qian R, Wang H, Guo Y (2005) Investigation of radical cation in electrophilic fluorination by ESI-MS. Org Lett 7: 3877-3880.
- Zhang X, Wang H, Guo Y (2006) Interception of the radicals produced in electrophilic fluorination with radical traps (Tempo, Dmpo) studied by electrospray ionization mass spectrometry. Rapid Commun Mass Spectrom 20: 1877-1882.
- Roithova J (2012) Characterization of reaction intermediates by ion spectroscopy. Chem Soc Rev 41: 547-559.
- Fabris D (2005) Mass spectrometric approaches for the investigation of dynamic processes in condensed phase. Mass Spectrom Rev 24: 30-54.
- Glish GL, Cooks RG (1978) The Fischer indole synthesis and pinacol rearrangement in the mass spectrometer. J Am Chem Soc 100: 6720-6725.
- Porter CJ, Beynon JH, Ast T (1981) The Modern Mass Spectrometer-A Complete Chemical Laboratory. Org Mass Spectrom 16: 101-114.
- McLafferty FW (1959) Mass spectrometric analysis. Molecular rearrangements. Anal Chem 31: 82–87.
- Cooks RG, Chen H, Eberlin MN, Zheng X, Tao WA (2006) Polar acetalization and transacetalization in the gas phase: the Eberlin reaction. Chem Rev 106: 188-211.
- Wang HY, Guo YL, Lu L (2004) Studies of rearrangement reactions of protonated and lithium cationized 2-pyrimidinyloxy-N-arylbenzylamine derivatives by MALDI-FT-ICR mass spectrometry. J Am Soc Mass Spectrom 15: 1820-1832.
- Wang HY, Liao YX , Guo YL, Tang QH, Lu L (2005) Interesting acid catalyzed O-N-type Smiles rearrangement reactions of 2-pyrimidinyloxy-N-arylbenzylamine derivatives. SynLett 8: 1239-1242.
- Xu C, Wang HY, Zhu FJ, Guo YL, Lu L (2011) Studies of gas-phase reactions of cationic iron complexes of 2-pyrimidinyloxy-N-arylbenzylamines by electrospray ionization tandem mass spectrometry. Rapid Commun Mass Spectrom 25: 169-178.
- Wang HY, Zhang X, Guo YL, Dong XC, Tang QH, et al. (2005) Sulfonamide bond cleavage in benzenesulfonamides and rearrangement of the resulting p-aminophenylsulfonyl cations: application to a 2-pyrimidinyloxybenzylaminobenzene sulfonamide herbicide. Rapid Commun Mass Spectrom 19: 1696-1702
- Wang HY, Zhang X, Qian R, Guo YL, Lu L (2006) Gas-phase sulfonyl-sulfinate rearrangement of protonated 4,6-dimethoxy-2-(methylsulfonyl)pyrimidine. Rapid Commun Mass Spectrom 20: 2773-2776.
- Wang HY, Zhang X, Guo YL, Lu L (2005) Mass spectrometric studies of the gas phase retro-Michael type fragmentation reactions of 2-hydroxybenzyl-N-pyrimidinylamine derivatives. J Am Soc Mass Spectrom 16: 1561-1573.
- Wang HY, Xu C, Zhu W, Liu GS, Guo YL (2012) Gas phase decarbonylation and cyclization reactions of protonated N-methyl-N-phenylmethacrylamide and its derivatives via an amide Claisen rearrangement. J Am Soc Mass Spectrom.
- Zhao ZX, Wang HY, Xu C, Guo YL (2010) Gas-phase synthesis of hydrodiphenylcyclopropenylium via nonclassical Favorskii rearrangement from alkali-cationized alpha,alpha'-dibromodibenzyl ketone. Rapid Commun Mass Spectrom 24: 2665-2672.
- Wang HY, Zhang X, Guo YL, Tang QH, Lu L (2006) Using tandem mass spectrometry to predict chemical transformations of 2-pyrimidinyloxy-N-arylbenzyl amine derivatives in solution. J Am Soc Mass Spectrom 17: 253-263.
- Agrawal D, Schröder D (2011) Insight into solution chemistry from gas-phase experiments. Organometallics 30: 32-35.
Citation: Zhang JT, Wang HY, Zhu W, Guo YL (2012) Mass Spectrometry: Insightful Window for Organic Chemistry. Organic Chem Curr Res 1: e116. Doi: 10.4172/2161-0401.1000e116
Copyright: ©2012 Zhang JT, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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