- Decomposition of ozonolysis peroxide products of (+)-α- and (+)-β-pinenes in methanol by Fe(III) salts
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The reaction of ozonolysis peroxide products of (+)-α and (+)-β-pinenes with Fe(III) salts in MeOH was studied. It was found that decomposition of methoxyhydroperoxides obtained via ozonolysis of (+)-β-pinene using FeCl3×6H2O occurre
- Garifullina,Salimova,Kasradze,Spirikhin,Kukovinets
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- Synthesis and surface spectroscopy of α-pinene isotopologues and their corresponding secondary organic material
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Atmospheric aerosol-cloud interactions remain among the least understood processes within the climate system, leaving large uncertainties in the prediction of future climates. In particular, the nature of the surfaces of aerosol particles formed from biogenic terpenes, such as α-pinene, is poorly understood despite the importance of surface phenomena in their formation, growth, radiative properties, and ultimate fate. Herein we report the coupling of a site-specific deuterium labeling strategy with vibrational sum frequency generation (SFG) spectroscopy to probe the surface C-H oscillators in α-pinene-derived secondary organic aerosol material (SOM) generated in an atmospheric flow tube reactor. Three α-pinene isotopologues with methylene bridge, bridgehead methine, allylic, and vinyl deuteration were synthesized and their vapor phase SFG spectra were compared to that of unlabeled α-pinene. Subsequent analysis of the SFG spectra of their corresponding SOM revealed that deuteration of the bridge methylene C-H oscillators present on the cyclobutane ring in α-pinene leads to a considerable signal intensity decrease (ca. 30-40%), meriting speculation that the cyclobutane moiety remains largely intact within the surface bound species present in the SOM formed upon α-pinene oxidation. These insights provide further clues as to the complexity of aerosol particle surfaces, and establish a framework for future investigations of the heterogeneous interactions between precursor terpenes and particle surfaces that lead to aerosol particle growth under dynamically changing conditions in the atmosphere.
- Upshur, Mary Alice,Vega, Marvin M.,Bé, Ariana Gray,Chase, Hilary M.,Zhang, Yue,Tuladhar, Aashish,Chase, Zizwe A.,Fu, Li,Ebben, Carlena J.,Wang, Zheming,Martin, Scot T.,Geiger, Franz M.,Thomson, Regan J.
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p. 8390 - 8398
(2019/09/30)
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- Dual stereoselectivity in the dialkylzinc reaction using (-)-β-pinene derived amino alcohol chiral auxiliaries
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(+)-Nopinone, prepared from naturally occurring (-)-β-pinene, was converted to the two regioisomeric amino alcohols 3-MAP and 2-MAP in very good yield and excellent isomeric purity. Amino alcohol 3-MAP was synthesized by converting (+)-nopinone to the corresponding α-ketooxime. This was reduced to the primary amino alcohol and was converted to the morpholino group through a simple substitution reaction. 3-MAP was characterized by X-ray crystallography, which displayed the rigidity of the pinane framework. Amino alcohol 2-MAP was prepared from its trans isomer 2, which in tum was synthesized via hydroboration/ oxidation of the morpholine enamine of (+)-nopinone. Two-dimensional NMR was used to characterize amino alcohol 2-MAP, and NOE was used to confirm its relative stereochemistry. These amino alcohols were employed as chiral auxiliaries in the addition of diethylzinc to benzaldehyde to obtain near-quantitative asymmetric induction in the products. The use of 3-MAP yielded (S)-phenylpropanol in 99% ee, and its regioisomer 2-MAP gave the opposite enantiomer, (R)-phenylpropanol, also in 99% ee. Other aromatic, aliphatic, and α,β-unsaturated aldehydes were implemented in this method, affording secondary alcohols in high yield and enantiomeric excess. Amino alcohols 2-MAP and 3-MAP were also found to be useful in the dimethylzinc addition reaction, both catalyzing the addition to benzaldehyde with nearly quantitative ee. Regioisomeric amino alcohols 2-MAP and 3-MAP, even though they were prepared from one enantiomer of nopinone, provide antipodal enantiofacial selectivity in the dialkylzinc addition reaction. This circumvents the necessity to synthesize amino alcohols derived from (-)-nopinone, which in tum requires the unnatural (+)-β-pinene. Possible mechanistic insights are offered to explain the dual stereoselectivity observed in the diethylzinc addition reaction involving regioisomeric, pseudo-enantiomeric amino alcohols 3-MAP and 2-MAP.
- Binder, Caitlin M.,Bautista, April,Zaidlewicz, Marek,Krzeminski, Marek P.,Oliver, Allen,Singaram, Bakthan
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supporting information; experimental part
p. 2337 - 2343
(2009/08/07)
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