- Organoselenium-Catalyzed Regioselective C?H Pyridination of 1,3-Dienes and Alkenes
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An efficient approach for organoselenium-catalyzed regioselective C?H pyridination of 1,3-dienes to form pyridinium salts has been developed. This method was also successfully applied to direct C?H pyridination of alkenes. Fluoropyridinium reagents, or initially loaded pyridine derivatives, acted as pyridine sources in the pyridination reactions. The obtained pyridinium salts could be further converted under different conditions. This work is the first example of catalytic C-2 direct C?H functionalization of 1,3-dienes and the first case of organoselenium-catalyzed C?H pyridination.
- Liao, Lihao,Guo, Ruizhi,Zhao, Xiaodan
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supporting information
p. 3201 - 3205
(2017/03/17)
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- Method of manufacturing compds. Allylnaphthol
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PROBLEM TO BE SOLVED: To provide a method for producing allyl compounds by dehydrative allylation of allyl alcohols and the like in the presence of a catalyst system consisting of a catalyst precursor and a ligand. SOLUTION: In the method for producing allyl compounds: the catalyst precursor consisting of a complex compound having a ruthenium atom is mixed with an (S, S) or (R, R) type ligand having a specific structure; and then, the allyl alcohols and a substrate are mixed to be reacted with each other. In the allyl alcohols: a carbon atom and a hydrogen atom are connected to a carbon atom in the third position or a carbon atom is connected to a carbon atom in the first position; and these carbon atoms are sp2or sp hybridized carbon atoms or these carbon atoms are connected to carbon atoms only. The substrate is a cyclic compound having carbonyl groups in the first and third positions and having a carbon atom in the second position wherein the carbon atom is connected to a carbon atom or a hydrogen atom. COPYRIGHT: (C)2013,JPO&INPIT
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Paragraph 0029-0041; 0049
(2018/08/23)
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- Interception of nazarov reactions of allenyl vinyl ketones with dienes: (3+2)- Versus (4+3)-cycloaddition and subsequent rearrangement
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Capture of the cyclic oxyallyl cation intermediates from the BF3-mediated Nazarov reactions of three allenyl vinyl ketones with various dienes was accomplished by (3+2)- and (4+3)-cycloaddition. The relative amounts of these types of products were dependent on the substitution on the diene, and this could be linked to steric hindrance. Treatment of the (3+2)-cycloaddition products with BF3·Et2O led mainly to decomposition but also to ring-opened molecules and ring-enlarged structures. The computed Gibbs energies of the (3+2)-cycloaddition products, the products of the acid treatment and of some transition states leading to rearranged products were compared.
- Morgan, Timothy D. R.,Lefort, Fran?ois M.,Li, Zhe,Marx, Vanessa M.,Boyd, Russell J.,Burnell, D. Jean
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supporting information
p. 2952 - 2959
(2015/04/27)
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- Rhodium-catalyzed chemo- and regioselective decarboxylative addition of β-ketoacids to allenes: Efficient construction of tertiary and quaternary carbon centers
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A rhodium-catalyzed chemo- and regioselective intermolecular decarboxylative addition of β-ketoacids to terminal allenes is reported. Using a Rh(I)/DPPF system, tertiary and quaternary carbon centers were formed with exclusively branched selectivity under mild conditions. Preliminary mechanism studies support that the carbon-carbon bond formation precedes the decarboxylation and the reaction occurs in an outer-sphere mechanism.
- Li, Changkun,Breit, Bernhard
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supporting information
p. 862 - 865
(2014/02/14)
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- Asymmetric dehydrative C-, N-, and O-allylation using Naph-diPIM-dioxo-i- Pr-CpRu/p-TsOH combined catalyst
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(S,S)- or (R,R)-Naph-diPIM-dioxo-i-Pr-CpRu(II) complex with a Bronsted acid catalyzes dehydrative intermolecular C-allylation with high enantio- and regioselectivity. The new soft Ru/hard H+ combined catalyst can also be used for intramolecular C-, N-, and O-allylations, giving nearly enantiomerically pure α-alkenyl-substituted cyclic compounds. As water is only the co-product, the synthetic process can be readily scaled up. Georg Thieme Verlag Stuttgart New York.
- Miyata, Kengo,Kitamura, Masato
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experimental part
p. 2138 - 2146
(2012/09/22)
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- Catalytic enantioselective 1,2-diboration of 1,3-dienes: Versatile reagents for stereoselective allylation
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More with boron: The development of catalytic enantioselective 1,2-diboration of 1,3-dienes enables a new strategy for enantioselective carbonyl allylation reactions (see scheme). These reactions occur with outstanding levels of stereoselection and can be applied to both monosubstituted and 1,1-disubstituted dienes. The carbonyl allylation reactions provide enantiomerically enriched functionalized homoallylic alcohol products. Copyright
- Kliman, Laura T.,Mlynarski, Scott N.,Ferris, Grace E.,Morken, James P.
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supporting information; experimental part
p. 521 - 524
(2012/03/11)
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- A chiral bidentate sp2-N ligand, naph-diPIM: Application to CpRu-catalyzed asymmetric dehydrative C-, N-, and O-allylation
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A handy new ligand: The CpRu complex (Cp=cyclopentadienyl) of a new type of chiral bisamidine ligand with a naphtho[1,2-b:7,8-b]dipyrroloimidazole (Naph-diPIM) skeleton with a Bronsted acid efficiently catalyzes dehydrative intermolecular C-allylation with high enantio- and regioselectivity. The catalytic system also gives nearly enantiomerically pure cycloalkanes and N- and O-heterocycles with a substrate/catalyst ratios of up to 10 000.
- Miyata, Kengo,Kutsuna, Hironori,Kawakami, Sho,Kitamura, Masato
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supporting information; experimental part
p. 4649 - 4653
(2011/06/27)
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- Ni(0)-catalyzed 1,4-selective diboration of conjugated dienes
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Figure Presented. A catalytic stereoselective 1,4-diboration of conjugated dienes with B2(pin)2 was accomplished with Ni(cod) 2 and PCy3 as the catalyst. This reaction broadens the substrate scope of current methods for catalytic diene diboration by including internal and sterically hindered dienes, and it proceeds efficiently at low catalyst loadings. The intermediate allylboronate was oxidized to the stereodefined allylic 1,4-diol.
- Ely, Robert J.,Morken, James P.
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supporting information; scheme or table
p. 4348 - 4351
(2010/11/19)
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- Cyclobutanones through SNi′ ring closure, a mechanistic study
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Mechanistic studies on the intramolecular nucleophilic substitution with allylic rearrangement (SNi′ reaction) and a new stereoselective access to substituted cyclobutanones are reported. 4,4-Dialkyl-5-oxohex-2E-en- 1-yl ethanesulfonates 4 were
- Lovchik, Martin A.,Goeke, Andreas,Frater, Georg
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p. 2427 - 2433
(2007/10/03)
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- A practical transformation of aldehydes into (E)-iodoalkenes with geminal dichromium reagents
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A catalytic cycle of a chromium salt in a stereoselective transformation of aldehydes to (E)-l-iodoalkenes using a geminal dichromium reagent, is assembled with zinc, Me3SiCl, and NaI in dioxane.
- Takai, Kazuhiko,Ichiguchi, Tetsuya,Hikasa, Shintaro
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p. 1268 - 1270
(2007/10/03)
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- (E)- And (Z)-1-(Phenylsulfonyl)-4-(trimethylsilyl)-2-butenes: Synthetic Equivalents for the 1-(1,3-Butadienyl) Anion and the 1,1-(1,3-Butadienyl) Dianion
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(E)- and (Z)-1-(phenylsulfonyl)-4-(trimethylsilyl)-2-butenes (7 and 8) are converted by n-BuLi to (E)- and (Z)-1-lithio-1-(phenylsulfonyl)-4-(trimethylsilyl)-2-butenes (15 and 16) with retention of initial stereochemistries. Reactions of 15 and 16 with electrophiles (protio and deuterio acids, primary, secondary, and benzyl halides, chloroformates, chlorothioformates, acid chlorides, epoxides, trialkylsilyl chlorides, and triethylgermanyl chloride) in THF or THF/HMPA give the corresponding (E)- and (Z)-1-(phenylsulfonyl)-1-substituted-4-(trimethylsilyl)-2-butenes (32) with stereochemical retention. That β,γ-unsaturated silyl sulfones 32 are formed instead of their α,β-unsaturated (conjugated) isomers are attributed to stabilizing multiple anionic and cationic hyperconjugation and to steric effects as in 29-31. Of importance in synthesis is that 32 are eliminated by TBAF at -20 to 0°C, thermally, or by column chromatography to (E)- (100 to > 93%) rather than (Z)-1-substituted-1,3-butadienes (38). Further, 32 undergo conversions by n-BuLi and various alkylating agents to (unconjugated) 1-(phenylsulfonyl)-1,1-disubstituted-4-(trimethylsilyl)-2-butenes (46) with retention of stereochemistry. Eliminations of 46 by fluoride ion, acid catalysis, or heat yield 1,1-disubstituted-1,3-butadienes (53). Silyl sulfones 7 and 8 are thus synthetic equivalents for the (E)-1-(1,3-butadienyl) anion (44) and the 1,1-(1,3-butadienyl) dianion (57). Silyl sulfones 7 and 8 also undergo efficient stereospecific intramolecular conversions by n-BuLi and α,ω-dihalides to 1,1-cycloalka-1-(phenylsulfonyl)-4-(trimethysilyl)-2-butenes (62 and 71) that are eliminated by fluoride ion, heat, or adsorption chromatography to 1,1-cycloalka-1,3-butadienes (72).
- Meagher, Timothy P.,Yet, Larry,Hsiao, Chi-Nung,Shechter, Harold
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p. 4181 - 4192
(2007/10/03)
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- Polylithiumorganic compounds - 23. 1: 3,4-dilithio-1,2-butadienes by addition of lithium metal to 1,4-unsymmetrically substituted butatrienes
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The synthesis of the highly reactive 1,4-unsymmetrically substituted butatrienes 12a-c is described. When employing a strict synthetic protocol, these alkatrienes react with lithium metal to 3,4-dilithio-1,2-butadienes 20a-c as stable intermediates. The structure of 20 is supported by IR and NMR spectroscopic evidence. The same dianionic intermediate can be prepared in one case by double deprotonation of the 1,2-butadiene 19. Upon derivatization, either 3,4-disubstituted 1,2-butadienes 24, 2,3-disubstituted 1,3-butadienes 25, or 1,4-disubstituted 2-butynes 26 are formed, depending on the nature of the electrophile employed. Copyright
- Maercker, Adalbert,Wunderlich, Hans,Girreser, Ulrich
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p. 6149 - 6172
(2007/10/03)
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- Highly efficient synthesis of alka-1,3-dien-2-yltitanium compounds from alka-2,3-dienyl carbonates. A new, practical synthesis of 1,3-dienes and 2-iodo-1,3-dienes
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Treatment of carbonates of alka-2,3-dien-1-ols 2 with (η2-propene)Ti(O-i-Pr)2 (1) resulted in oxidative addition to afford 1,3-dien-2-yltitanium compounds 3, which react readily with electrophiles such as H+, I2
- Okamoto, Sentaro,Sato, Hiroyoshi,Sato, Fumie
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p. 8865 - 8868
(2007/10/03)
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Reaction of alkyl hydroperoxides (1(ary), 2(ary) or 3(ary)) upon tertiary alkyl trichloroacetimidates under acidic catalysis yielded unsymmetrical dialkyl peroxides with yields in the range 30-70%.
- Bourgeois,Montaudon,Maillard
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p. 2477 - 2484
(2007/10/02)
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- Preparation of Lactones via Tricarbonyliron-Lactone Complexes
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A number of tricarbonyliron-lactone complexes have been prepared from vinyl oxirans by treatment with pentacarbonyliron.In certain cases two ν3-allyl complexes were isolated from a single vinyl oxiran.Oxidation of the complexes by cerium (IV) ammonium nitrate in acetonitrile leads predominantly to β-lactones.The stereochemical integrity of the initial complexes is reflected in the formation of the oxidation products.Reduction of these products with lithium aluminium hydride gave the expected diols.
- Annis, Gary D.,Ley, Steven V.,Self, Christopher R.,Sivaramakrishnan, Ramamoorthy
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p. 270 - 277
(2007/10/02)
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