The Experts below are selected from a list of 144 Experts worldwide ranked by ideXlab platform
Ryosuke Matake - One of the best experts on this subject based on the ideXlab platform.
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a grignard type phase vanishing method generation of organomagnesium reagent and its subsequent addition to carbonyl compounds
ChemInform, 2015Co-Authors: Hiroshi Matsubara, Yuki Niwa, Ryosuke MatakeAbstract:Grignard reagents are efficiently generated in a quadraphasic phase-vanishing system containing diethyl ether, magnesium, perfluoropolyether, and Iodoalkane.
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a grignard type phase vanishing method generation of organomagnesium reagent and its subsequent addition to carbonyl compounds
Synlett, 2015Co-Authors: Hiroshi Matsubara, Yuki Niwa, Ryosuke MatakeAbstract:A quadraphasic phase-vanishing system comprised of diethyl ether, magnesium, perfluoropolyether, and Iodoalkane efficiently generated the corresponding Grignard reagents, which subsequently added to carbonyl compounds in the ether layer to afford alkylated alcohols in good yields.
David H Thompson - One of the best experts on this subject based on the ideXlab platform.
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improved plasmalogen synthesis using organobarium intermediates
Journal of Organic Chemistry, 2007Co-Authors: Jeroen Van Den Bossche, Junhwa Shin, David H ThompsonAbstract:An improved synthesis of plasmalogen type lipids is described. Transmetalation of lithioalkoxy allyl intermediates with BaI2 and subsequent alkylation with 1-Iodoalkanes enables the stereoselective formation of O-(Z)-alkenyl ether as precursors for the synthesis of plasmenyl- and bisplasmenylcholines. This method provides a simple and adaptable approach for the stereocontrolled synthesis of plasmenyl derivatives with variations at the sn-1, sn-2, and sn-3 positions of the glycerol backbone.
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direct synthesis of plasmenylcholine from allyl substituted glycerols
Journal of Organic Chemistry, 2003Co-Authors: Junhwa Shin, David H ThompsonAbstract:We report a new method for the facile preparation of plasmenylcholine via reaction of lithioalkoxy allyl intermediates with 1-Iodoalkanes as the key step in the stereoselective formation of 1'-(Z)-alkenyl glyceryl ethers. The allyl anion intermediate is prepared by treating mono- or disiloxy-protected 1-allylglycerol precursors with s-BuLi at -65 to -80 degrees C. Subsequent addition of 1-Iodoalkane solutions at low temperature gives moderate yields of gamma-coupled, Z-vinyl ethers as the major product and alpha-coupled product as the minor component. Several different preparative strategies for the total synthesis of plasmalogens are enabled by this simple transformation.
Hiroshi Matsubara - One of the best experts on this subject based on the ideXlab platform.
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a grignard type phase vanishing method generation of organomagnesium reagent and its subsequent addition to carbonyl compounds
ChemInform, 2015Co-Authors: Hiroshi Matsubara, Yuki Niwa, Ryosuke MatakeAbstract:Grignard reagents are efficiently generated in a quadraphasic phase-vanishing system containing diethyl ether, magnesium, perfluoropolyether, and Iodoalkane.
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a grignard type phase vanishing method generation of organomagnesium reagent and its subsequent addition to carbonyl compounds
Synlett, 2015Co-Authors: Hiroshi Matsubara, Yuki Niwa, Ryosuke MatakeAbstract:A quadraphasic phase-vanishing system comprised of diethyl ether, magnesium, perfluoropolyether, and Iodoalkane efficiently generated the corresponding Grignard reagents, which subsequently added to carbonyl compounds in the ether layer to afford alkylated alcohols in good yields.
Jim J Lin - One of the best experts on this subject based on the ideXlab platform.
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the role of the iodine atom adduct in the synthesis and kinetics of methyl vinyl ketone oxide a resonance stabilized criegee intermediate
Physical Chemistry Chemical Physics, 2020Co-Authors: Yenhsiu Lin, Wen Chao, Kaito Takahashi, Jim J LinAbstract:Isoprene is the most abundant alkene in the atmosphere. Ozonolysis of isoprene produces three very reactive carbonyl oxides (Criegee intermediates), including formaldehyde oxide, methyl vinyl ketone oxide (MVKO, CH3(C2H3)COO), and methacrolein oxide. The latter two Criegee intermediates are resonance-stabilized due to the vinyl group. Recently, the electronic spectrum of thermalized MVKO has been reported [Caravan, et al., Proc. Natl. Acad. Sci. U. S. A., 2020, 117, 9733]. In this work, we utilized this strong UV/visible absorption to investigate the reaction kinetics of MVKO with SO2 under a wide pressure range of 4 to 700 Torr. We followed a new method [Barber, et al., J. Am. Chem. Soc., 2018, 140, 10866], in which MVKO is produced through the reaction of a resonance-stabilized iodoalkene radical with O2. The experimental data are consistent with a kinetic model that the reaction goes through an adduct of CH3(C2H3)CIOO, similar to the cases of H/alkyl substituted Criegee intermediates. However, different from the H/alkyl adducts, which are stable over the time scales of typical kinetic experiments, this vinyl adduct CH3(C2H3)CIOO is less stable and decomposes to MVKO + I at a time scale of 10-3 s (faster at higher temperature), consistent with the results of quantum chemistry calculations and the fact that the resonance stabilization is disrupted at the adduct structure. The adduct decomposition is the major pathway that forms MVKO for pressures higher than 50 Torr. In addition, temperature dependence has been investigated for 278-319 K. The experimental activation energy of the adduct decomposition was measured to be 12.7 ± 0.3 kcal mol-1, consistent with the calculated dissociation energy of the adduct to MVKO + I (14 kcal mol-1). Furthermore, the temperature dependent rate coefficient of MVKO + SO2 reaction has been measured to be kSO2 = (4.0 ± 0.6) × 10-11 cm3 s-1 at 4-700 Torr and 298 K with a negative activation energy of -3.7 ± 0.4 kcal mol-1.
Kiitiro Utimoto - One of the best experts on this subject based on the ideXlab platform.
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a dramatic effect of a catalytic amount of lead on the simmons smith reaction and formation of alkylzinc compounds from Iodoalkanes reactivity of zinc metal activation and deactivation
Journal of Organic Chemistry, 1994Co-Authors: Kazuhiko Takai, Terutaka Kakiuchi, Kiitiro UtimotoAbstract:A trace amount of lead found in zinc derivedfrom the pyrometallurgy smelting method decreases the reactivity of zinc toward diiodomethane and Iodoalkanes substantially, and this negative effect can be suppressed by the addition of a catalytic amount of Me 3 SiCl
