Synthesis of Alkyl-Substituted Six-Membered Lactones through Ring-Closing Metathesis of Homoallyl Acrylates. An Easy Route to Pyran-2-ones, Constituents of Tobacco Flavor
摘要:
The ring-closing metathesis (RCM) reactions of homoallylic acrylates bearing alkyl substituents on various positions of their skeleton afford the corresponding pentenolides in the presence of carbene ruthenium catalysts. For R-3 = R-4 = H, or R-3 = Me, R-4 = H, the reactions are catalyzed by complex [RuCl2(PCy3)(2)(CHPh)], while a second-generation Grubbs catalyst is required when R-3 = H and R-4 = Me, R-3 = R-4 = Me, or R-3 = i-Pr and R-4 = H. Alkyl substitution at the homoallylic carbon (R-1, R-2) increases the yield of the reaction when both the acrylic and/or homoallylic double bonds are methyl-substituted. The interaction of the catalyst with the substrate in the initiation stage involves the homoallylic double bond rather than the acrylic moiety, and the resulting alkylidene species from the first-generation Grubbs catalyst can be observed by H-1 and P-31 NMR. The racemic tobacco constituents 4-isopropyl-5,6-dihydropyran-2-one and 4-isopropyltetrahydropyran-2-one are prepared via a short reaction sequence, involving the RCM reaction as the key transformation.
Cyclizations in the Addition of Alkylmercury Halides to Dienes and Enynes
作者:Glen A. Russell、Chaozhong Li、Ping Chen
DOI:10.1021/ja9601898
日期:1996.1.1
or CH2CHC(O)OC(Me)2CHCH2. The radicals t-BuCH2CH•C(O)C(Me)2(CH2)nCHCH2 cyclize mainly in the 6-endo mode for n = 1 and more rapidly in the 6-exo mode for n = 2, while the radicals t-BuCH2CH•C(O)OC(Me)2(CH2)nCHCH2 cyclize only in the exo mode for n = 0 or 1 but with a faster rate for 5-exo-cyclization. Gem-dimethyl substitution adjacent to the alkyl oxygen accelerates the 5-exo-cyclization of the ester
将叔丁基卤化汞光刺激加成到 1,6-二烯和烯炔,包括 (CH2CHCH2)2X,其中 X = CH2、C(COEt)2、O 或 NCH2CHCH2,形成由 5-外环化产生的初级烷基卤化汞加合物自由基,t-BuCH2CH•CH2XCH2CHCH2。这些自由基过程的动力学链长度很低,在 Me2SO 中 35 °C 时的范围为 3-7。在光刺激下将 t-BuHgI 添加到 CH2CHP(O)(OR)OCH2CHCH2(R = H 或烯丙基)、CH2CHC(O)N(R)CH2CHCH2(R = Me、Ph 或 CH2CHCH2) 或 CH2CHC(O)OC(Me)2CHCH2。基团 t-BuCH2CH•C(O)C(Me)2(CH2)nCHCH2 在 n = 1 时主要以 6-endo 模式环化,在 n = 2 时以 6-exo 模式更快地环化,而基团 t-BuCH2CH•C(O)OC(Me)2(CH2)nCHCH2
Synthesis of epoxy (meth)acrylic esters by selective epoxidation of unsaturated (meth)acrylic esters using the system H2O2 - Na2WO4 under phase transfer catalysis
作者:Y. Fort、A. Olszewski-Ortar、P. Caubere
DOI:10.1016/s0040-4020(01)90120-6
日期:1992.1
Selective epoxidation of unsaturated (meth)acrylic esters by various classical epoxidizing agents was investigated. It is shown that high selectivity and good yields are obtained by using the system H2O2 (20%) - Na2WO4 under phase transfer catalysis. Under these conditions, the rigorous control of the temperature and of the initial pH allows to prevent polymerization during these selective epoxidations
研究了各种经典的环氧化剂对不饱和(甲基)丙烯酸酯的选择性环氧化。结果表明,在相转移催化下,通过使用H 2 O 2(20%)-Na 2 WO 4体系可以得到高选择性和高收率。在这些条件下,严格控制温度和初始pH值可防止在这些选择性环氧化过程中发生聚合。结果表明,环氧化的选择性取决于两个双键亲核性的差异。
Nickel-Catalyzed Three-Component Reductive Alkylacylation of Electron-Deficient Activated Alkenes
作者:Lin Wang、Chuan Wang
DOI:10.1021/acs.orglett.0c03210
日期:2020.11.20
alkylacylation of electron-deficient activated alkenes with tertiary alkyl bromides and acid anhydrides. This method enables the efficient preparation of a variety of ketones with broad substrate scope and high functionality tolerance starting from simple precursors. On the basis of the preliminary mechanistic investigations, a catalytic cycle involving the synergistic interaction of nickel, zinc, and MgCl2
ELECTROLYTIC SOLUTION, ELECTROCHEMICAL DEVICE, LITHIUM ION SECONDARY BATTERY, AND MODULE
申请人:DAIKIN INDUSTRIES, LTD.
公开号:US20200280096A1
公开(公告)日:2020-09-03
An electrolyte solution containing a compound represented by the following formula (1):
wherein R
101
and R
102
are the same as or different from each other and are each a hydrogen atom, a fluorine atom, or an alkyl group optionally containing a fluorine atom; and R
103
is an alkyl group or an organic group containing an unsaturated carbon-carbon bond. Also disclosed is an electrochemical device and lithium ion secondary battery including the electrolyte solution, and a module including the electrochemical device or lithium ion secondary battery.
Fast and unprecedented chemoselective hydroformylation of acrylates with a fluoropolymer ligand in supercritical CO2
作者:Yulai Hu、Weiping Chen、Anna M. Banet Osuna、Jon A. Iggo、Jianliang Xiao
DOI:10.1039/b201166b
日期:2002.3.21
A fluorous polymeric phosphine, when combined with supercriticalCO2 (scCO2) and rhodium, effects fast and highly chemoselective hydroformylation of acrylates, one of the least reactive olefins in hydroformylation reactions.