- 1,3-Asymmetric Induction in Diastereoselective Allylations of Chiral N-Tosyl Imines
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Lewis acid mediated allylations of β-alkoxy N-tosyl imines using allyltrimethylsilane lead to 3-alkoxy homoallylic N-tosyl amines with anti-selectivity. Two methods of Cu(OTf)2-mediated allylations are reported herein, demonstrating that diastereoselectiv
- Lo, Anna,Gutierrez, David A.,Toth-Williams, Garrett,Fettinger, James C.,Shaw, Jared T.
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supporting information
p. 2773 - 2778
(2022/02/07)
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- NOVEL RUTHENIUM COMPLEX AND METHOD FOR PREPARING METHANOL AND DIOL
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Provided is a method for preparing methanol and diol from cyclic carbonate, comprising: under a hydrogen atmosphere, in an organic solvent, and with the presence of a ruthenium complex (Ru(L)XYY') and an alkali, conducting a hydrogenation reduction reaction on the cyclic carbonate or polycarbonate to obtaib methanol and diol. Also provided is a ruthenium complex prepared from ruthenium and a tridentate amido diphosphine ligand. Also provided is a deuterated methanol and deuterated diol preparation method by substituting the hydrogen and ruthenium complex with deuterium.
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Paragraph 0089
(2015/09/23)
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- Direct conversion of β-hydroxyketones to cyclic disiloxanes
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β-Hydroxyketones can be directly converted to cyclic disiloxanes using diphenylchlorosilane in the presence of imidazole and an amine base. The reaction is proposed to proceed via a nucleophilic activation mechanism through a cyclic chairlike transition state affording hydrosilylated products with high diastereoselectivity.
- O'Neil, Gregory W.,Miller, Michael M.,Carter, Kyle P.
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supporting information; scheme or table
p. 5350 - 5353
(2011/01/05)
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- Use of thio derivatives as perfuming and flavoring ingredients
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The compounds of formula in the form of any one of their isomers or of mixtures thereof, and wherein R represents a hydrogen atom or an acetyl group, R1 represents a methyl or an ethyl group and R2 represents a C3-C4 linear or branched alkyl group, are useful for the perfume and flavor industries.
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- Use of thio derivates as perfuming and flavoring ingredients
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The compounds of formula in the form of any one of their isomers or of mixtures thereof, and wherein R represents a hydrogen atom or an acetyl group, R1 represents a methyl or an ethyl group and R2 represents a C3-C4 linear or branched alkyl group, are useful for the perfume and flavor industries.
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- 1-Methoxyhexane-3-thiol, a powerful odorant of clary sage (Salvia sclarea L.)
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The peculiar and highly diffusive odor signal of flowering clary-sage plants (Salvia sclarea L.) was identified to derive from trace amounts of 1 -methoxyhexane-3-thiol (1) by mass-spectrometry analysis and confirmed by comparison with synthetic racemic thiol (±)-1. The enantiomers (S)- and (R)-1 were prepared by enantioselective synthesis, and the absolute configuration of (S)-1 was fully corroborated by X-ray-diffraction analysis of the crystalline thioester (1′S,1S)-2. Compound (S)-1 is one of the most powerful odorants known, with a detection threshold of 0.04·10-3 ng/l air, and is, with its herbaceous-green, alliaceous, and perspiration profile, key to the fragrance of clary-sage flowers and of the freshly distilled essential oil. As a consequence of its unique odor, 1 was also suspected to be part of the volatiles of a Ruta species where it was subsequently identified together with its homologue, 1-methoxyheptane-3-thiol (3), 1-methoxy-4-methylpentane-3-thiol (4), and the known 4-methoxy-2-methylbutane-2-thiol (5). The syntheses of (±)-3 and (±)-4 as well as of the enantiomer (R)-4 are described. In both natural fractions, the ratio (S)-1/(R)-1 was slightly in favor of the (S)-enantiomer. Natural 4 has (R)-configuration.
- Van De Waal, Matthijs,Niclass, Yvan,Snowden, Roger L.,Bernardinelli, Geerald,Escher, Sina
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p. 1246 - 1260
(2007/10/03)
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- Intramolecular H-Transfer Reactions During the Decomposition of Alkylhydroperoxides in Hydrocarbons as the Solvents
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Eight defined primary and secondary alkylhydroperoxides were decomposed in n-alkanes as the solvent, mostly in the presence of manganese stearate.In all cases the corresponding alcohols and carbonyl compounds were formed as the main products with yields of 60-90percent.Besides, difunctional products were formed by an intramolecular H-transfer in the alkoxy radicals corresponding to the starting hydroperoxides.Products possibly formed by an intramolecular H-transfer in the corresponding alkylperoxy radical could be found only in the case of 4-methyl-2-hydroperoxy pentane.The amount of products formed by intramolecular H-transfer depended on the nature of the C-H bond in δ-position to the original hydroperoxy group and lay between 4percent (primary C-H in the case of 4-hydroperoxy heptane) and 13percent (tertiary C-H in the case of 2-hydroperoxy-5-methyl hexane) with respect to the starting hydroperoxide.The amount of products formed by oxidative attack of the alkoxy and alkylperoxy radicals at the normal paraffins used as the solvents was unexpectedly low (always less than 10percent with respect to the starting hydroperoxide).An increment system is proposed for the calculation of 13C-nmr shifts in alkyl hydroperoxides.
- Jinsheng, Li,Pritzkow, Wilhelm,Voerckel, Volkmar
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- REGIOSELECTIVE TITANIUM MEDIATED REDUCTIVE OPENING OF 2,3-EPOXY ALCOHOLS
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Lithium borohydride reduction of 2,3-epoxy alcohols was shown to yield 1,2-diols in high regioselectivity with the aid of titanium tetraisopropoxide in benzene solution.
- Dai, Li-xin,Lou, Bo-liang,Zhang, Ying-zhi,Guo, Guang-zhong
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p. 4343 - 4346
(2007/10/02)
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- REGIO- AND STEREOSELECTIVE RING OPENING OF EPOXY ALCOHOLS WITH ORGANOALUMINIUM COMPOUNDS LEADING TO 1,2-DIOLS
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Introduction of alkyl, alkynyl group, or hydride occurs regioselectively at the 3 position of the epoxy alcohols with inversion of the configuration upon treatment with organoaluminium reagents to produce vic-diols.
- Suzuki, Toshifumi,Saimoto, Hiroyuki,Tomioka, Hiroki,Oshima, Koichiro,Nozaki, Hitosi
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p. 3597 - 3600
(2007/10/02)
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