- Rhodium-catalysed substitutive arylation of cis-allylic diols with arylboroxines
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Substitutive arylation of cis-allylic diols occurs upon treatment with arylboroxines in the presence of a rhodium(i) catalyst; the reaction proceeds through the addition of an intermediate arylrhodium(i) species across the carbon-carbon double bond and su
- Miura, Tomoya,Takahashi, Yusuke,Murakami, Masahiro
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- Rhodium-Catalyzed Diverse Arylation of 2,5-Dihydrofuran: Controllable Divergent Synthesis via Four Pathways
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The rhodium-catalyzed controllable diverse arylation of 2,5-dihydrofuran with arylboronic acids is reported. By fine-tuning of the reaction conditions, four different ring-opening or oxidative arylation pathways are controlled in the rhodium-catalyzed ary
- Dou, Xiaowei,Hayashi, Tamio,Lu, Tao,Xing, Junhao,Ye, Bihai,Zhu, Wanjiang
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p. 2958 - 2963
(2020/03/23)
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- The Palladium-Catalyzed Cross-Coupling Reaction of Organosilicon Compounds with Allylic Carbonates or Diene Monoxides
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The cross-coupling reaction of allylic carbonates with organosilanes was found to proceed without fluoride ion activation under mild conditions by using a coordinatively unsaturated palladium complex as a catalyst.The reaction was assumed to proceed through an allylpalladium alkoxide derived from the allylic carbonate substrate and a palladium(0) species, the alkoxo ligand activating the organosilicon reagent.Likewise, diene monoxides also underwent cross-coupling with alkenyl- and arylfluorosilanes in moderate to high yields.
- Matsuhashi, Hayao,Asai, Satoshi,Hirabayashi, Kazunori,Hatanaka, Yasuo,Mori, Atsunori,Hiyama, Tamejiro
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p. 1943 - 1952
(2007/10/03)
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- Friedel-Crafts Reactions of Some Conjugated Epoxides
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The Friedel-Crafts (FC) reactions of (1,2-epoxyethyl)benzene, 1,2-epoxy-1-p-tolylethane, 1,2-epoxy-1-(p-methoxyphenyl)ethane, 1,2-epoxy-3-butene, and 1,2-epoxy-2-methyl-3-butene were examined under various conditions.Reaction time, temperature, Lewis acid, Lewis acid concentration, and solvent were varied.For (1,2-epoxyethyl)benzene (1), aromatic nucleophilicity was shown to be an important factor in promoting good FC yields.It was also shown that para carbocation stabilizing substituents on 1 did not improve FC yields.Vinyloxirane yielded primary products from direct ring opening (2-aryl-3-buten-1-ols) and conjugate addition (4-aryl-2-buten-1-ols) and secondary products (1,4-diaryl-2-butenes).Increased reaction time or catalyst concentration increases the proportion of secondary products.The primary and secondary FC pathways gave an excellent opportunity for study of the effects on product distributions of the use of aluminum chloride, boron trifluoride etherate, and stannic chloride Lewis acids.A significant FC reaction yield was not obtained with 1,2-epoxy-2-methyl-3-butene and toluene under the same conditions used for 1,2-eopoxy-3-butene.Presumably this results from steric effects.All products can be explained by attack of the aromatic nucleophile on the epoxide position (or positions) most capable of stabilizing incipient positive character.The epoxide is also less electrophilic than other alkylating agents under similar conditions.An explanation for this is given.
- Taylor, Stephen K.,Clark, Daniel L.,Heinz, Karl L.,Schramm, Scott B.,Westermann, Cindy D.,Barnell, Koleen K.
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p. 592 - 596
(2007/10/02)
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