28771-65-5Relevant academic research and scientific papers
ZnI2/Zn(OTf)2-TsOH: A versatile combined-Acid system for catalytic intramolecular hydrofunctionalization and polyene cyclization
Chou, Ting-Hung,Yu, Bo-Hung,Chein, Rong-Jie
supporting information, p. 13522 - 13525 (2019/11/14)
A mild and efficient combined-Acid system using a zinc(ii) salt [ZnI2 or Zn(OTf)2] and p-Toluene sulfonic acid (TsOH) was investigated for catalytic cationic cyclizations, including intramolecular hydrocarboxylation, hydroalkoxylation, hydroamination, hydroamidation, hydroarylation and polyene cyclizations. This reaction provides easy access to five-and six-membered O-and N-containing saturated heterocyclic compounds, tetrahydronaphthalene derivatives and polycyclic skeletons in excellent yield with perfect Markovnikov selectivity and under mild conditions. The operational simplicity, broad applicability, and use of inexpensive commercially available catalysts make this protocol superior to existing methodologies.
Enantioselective Bromolactonization of Trisubstituted Olefinic Acids Catalyzed by Chiral Pyridyl Phosphoramides
Nishikawa, Yasuhiro,Hamamoto, Yuhta,Satoh, Rika,Akada, Naho,Kajita, Shuhei,Nomoto, Marina,Miyata, Megumi,Nakamura, Madoka,Matsubara, Chinatsu,Hara, Osamu
supporting information, p. 18880 - 18885 (2018/12/04)
Enantioselective bromolactonization of trisubstituted olefinic acids producing synthetically useful chiral lactones with two contiguous asymmetric centers has remained mainly unexplored except for the 6-exo cyclization mode. In this work, the 5-exo- and 6
Asymmetric bromolactonization catalyzed by a C3-symmetric chiral trisimidazoline
Murai, Kenichi,Matsushita, Tomoyo,Nakamura, Akira,Fukushima, Shunsuke,Shimura, Masato,Fujioka, Hiromichi
supporting information; experimental part, p. 9174 - 9177 (2011/02/26)
A productive alliance: In an enantioselective organocatalytic bromolactonization of 5-substituted hex-5-enoic acids (see scheme), it appears that the formation of an ion pair through interaction of the trisimidazoline catalyst 1 with the substrate both cr
Unified oxidation protocol for the synthesis of carbonyl compounds using a manganese catalyst
Kamijo, Shin,Amaoka, Yuuki,Inoue, Masayuki
experimental part, p. 2475 - 2489 (2010/09/06)
We have developed a unified protocol for the oxidation of ethers, benzylic compounds, and alcohols to carbonyl compounds. The protocol uses catalytic amounts of manganese(II) chloride tetrahydrate and tri(t-butyl)-2,2':6',2Prime;- terpyridine in combination with a stoichiometric amount of either m-chloroperbenzoic acid (MCPBA) or potassium hydrogen peroxysulfate (KHSO 5). A reagent system consisting of the Mn catalyst and MCPBA permitted the chemoselective sp3 C-H oxidation of alkyl ethers and benzylic compounds to generate the corresponding ketones. Alternatively, the water-soluble inorganic salt KHSO5 in combination with the Mn catalyst was used to oxidize alcohols to ketones or carboxylic acids. Importantly, the Mn catalyst/KHSO5 system eliminates technical difficulties associated with the isolation of carboxylic acid products. All the oxidations presented in this feature article proceed at sup-ambient temperature in an aerobic atmosphere, and can therefore be used in practical syntheses of complex organic molecules. Georg Thieme Verlag Stuttgart · New York.
A new synthesis of lactones from tertiary alkenylcarbinols by cobalt-catalyzed photocarbonylation under ambient conditions
Chow, Yuan L.,Huang, Yu-Jin,Dragojlovic, Veljko
, p. 740 - 742 (2007/10/02)
In the presence of a Co catalyst, tertiary vinyl-, propenyl-, and allylcarbinols were chelatively cycloadded to carbon monoxide to produce lactones by xanthone-sensitized photoreaction in tetrahydrofuran, under CO at 1 atmosphere and at room temperature.At lower temperatures the isomerization of alkenyl-carbinols was suppressed and lactones were obtained with improved selectivity.The photoprocess was facilitated by addition of pyridine or hydrogen and retarded in presence of amines or phosphines.Mechanistic interpretations for the process and the accompanying effects are discussed.Key words: chelative carbonylation, photocarbonylation, carbonylation of olefins, lactones synthesis from alkenylalcohols.
DIRECT SYNTHESIS OF δ-LACTONES FROM 2-(3-LITHIOPROPYL)-1,3-DIOXOLANE AND CARBONYL COMPOUNDS
Ramon, Diego J.,Yus, Miguel
, p. 3767 - 3770 (2007/10/02)
The reaction of 2-(3-lithiopropyl)-1,3-dioxolane (2), prepared in situ by lithiation of the chloroacetal 1 with lithium naphthalenide at -78 deg C, with aldehydes and ketones followed by hydrolysis with hydrochloric acid and final oxidation with PCC or Jones reagent yields the corresponding δ-lactones 5.
LIGHT-INDUCED FREE-RADICAL REACTIONS OF 2-METHOXY-6-METHYLTETRAHYDROPYRAN: IRREVERSIBLE RING OPENING AND MULTISITE HYDROGEN ABSTRACTION
Babcock, Bruce W.,Dimmel, Donald R.,Graves, David P.,McKelvey, Ronald D.
, p. 736 - 742 (2007/10/02)
Acetophenone-initiated photodegradation of cis-2-methoxy-4-methyltetrahydropyran (7) in benzene solvent produced six products.The structures of the products, and studies using optically active 7, showed that hydrogen abstraction occurs at both C-2 and C-6 of the tetrahydropyran ring.The products derived from the C-2 radical indicated two pathways for this radical: ring opening and loss of methyl, which is consistent with previous work on other similar systems.Results with optically active 7 showed that the ring-opening pathway is irreversible.Generation of an open-chain radical independently also showed that cyclization to a six membered ring does not occur.The products from the photodegradation were trans-2-methoxy-6-methyltetrahydropyran (8), methyl hexanoate (10), 6-methyltetrahydropyran-2-one (9), methyl 5-phenylhexanoate (11), 1,7-dimethyl-7-phenyl-6,8-dioxobicyclooctane (13), and 2-methoxy-2-(1-phenyl-1-hydroxyethyl)-6-methyltetrahydropyran (12).The yield of lactone 9 was found to be sensitive to the amount of residual oxygen present during the photolysis.
