- Tracking the leaving group in the remote activation of O-2-[(propan-2-yl)sulfinyl]benzyl (OPSB) glycoside
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In our recently developed interrupted Pummerer reaction mediated glycosylation with O-2-[(propan-2-yl)sulfinyl]benzyl (OPSB) glycosides as glycosyl donors, the anomeric leaving group was recovered as a benzyl alcohol which didn't affect the glycosylation efficiency. To investigate the mechanism of the occurrence of this alcohol, an 18O isotopic labeling reaction was carried out to track the leaving group. It was found that the benzyl alcohol was generated during the aqueous work up process from an inactive cyclic oxo-sulfonium ion intermediate. It was also proved that H2O prefer to attack the sulfur atom position during the hydrolysis of the intermediate.
- Chen, Wei,Zeng, Jing,Wang, Hao,Xiao, Xiong,Meng, Lingkui,Wan, Qian
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Read Online
- Steric hindrance effects in tripodal ligands for extraction and back-extraction of Ag+
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A novel series of tripodal ligands with thiophenylether arms connected to an anchoring nitrogen has been investigated. Seven tripodal ligands were synthesized by combining methyl, isopropyl, and tert-butyl residue bearing thiophenylether sites as groups w
- Hiruta, Yuki,Watanabe, Takafumi,Nakamura, Etsuko,Iwasawa, Naoko,Sato, Hiroyasu,Hamada, Kensaku,Citterio, Daniel,Suzuki, Koji
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p. 9791 - 9798
(2014/03/21)
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- Syntheses, structures, and catalytic activities of hemilabile thioether-functionalized NHC complexes
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Four imidazolium (5a/b) and benzimidazolium (6a/b) salts with hemilabile alkyl-aryl thioether functions have been prepared via a straightforward and modular pathway in order to compare their reactivities toward palladation. Reaction of 5a/b with Pd(OAc)s
- Huynh, Han Vinh,Yeo, Chun Hui,Chew, Ying Xia
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experimental part
p. 1479 - 1486
(2010/05/15)
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- Control of the orientation of the aldehyde group in 2-(alkylthio)benzaldehydes by the directional lone-pair on sulfur
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The (1)H nmr spectral parameters for 2-alkylthio derivatives benzaldehyde (alkyl = CH3, CH2CH3, CH(CH3)2, C(CH3)3) are used to show that the O-syn conformation of the aldehyde group decreases from 40percent for the methyl to zero for the tert-butyl compound in CCl4 solution at about 300 K.It appears that the alkylthio groups twist out of the benzene plane to the same extent as in the alkyl phenyl sulfides and that is the concomitant approaches of the 3p lone-pairs on sulfur into the ring plane which, by repulsive interactions with the C=O bond, determine the conformations of the aldehyde group.The spectral parameters display interesting changesas the size of the alkyl group increases.For example, the chemical shift of the aldehydic proton is larger than that reported for any other benzaldehyde derivative in CCl4 solution.
- Schaefer, Ted,Penner, Glenn H.,Davie, Kerry J.,Sebastian, Rudy
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p. 777 - 781
(2007/10/02)
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