- Palladium(II)-Catalyzed meta-C-H Olefination: Constructing Multisubstituted Arenes through Homo-Diolefination and Sequential Hetero-Diolefination
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Divinylbenzene derivatives represent an important class of molecular building blocks in organic chemistry and materials science. Reported herein is the palladium-catalyzed synthesis of divinylbenzenes by meta-C-H olefination of sulfone-based arenes. Successful sequential olefinations in a position-selective manner provided a novel route for the synthesis of hetero-dialkenylated products, which are difficult to access using conventional methods. Additionally, 1,3,5-trialkenylated compounds can be generated upon successful removal of the directing group. Jockeying for position: Reported herein is the palladium-catalyzed synthesis of mono- and divinylbenzenes by meta-C-H olefination of benzyl sulfones. Successful sequential olefinations in a position-selective manner provided a novel route for the synthesis of hetero-dialkenylated products, which are difficult to access using conventional methods. DG=directing group.
- Bera, Milan,Maji, Arun,Sahoo, Santosh K.,Maiti, Debabrata
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- Olefination with Sulfonyl Halides and Esters: E-Selective Synthesis of Alkenes from Semistabilized Carbanion Precursors
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Carbanions of sulfonyl halides and activated sulfonates add to carbonyl compounds, and so-formed aldol-type adducts spontaneously fragment into olefins. This transformation mimics the one-pot Julia olefination with (hetero)aryl sulfones, but the mechanism of fragmentation involves a four-membered intermediate, typical for reactivity of phosphorus reagents. Moreover, in contrast to the reactions of sulfones, sulfonates of fluorinated alcohols (TFE and HFI) produce byproducts that are easily removed during workup. In our report, we focus on reactions of unstabilized and semistabilized carbanion precursors: alkylsulfonates, and allyl- and benzylsulfonates, respectively. In particular for semistabilized systems, olefins were synthesized as predominant E isomers in good yields. The presented studies reveal that optimal reaction conditions, including the type of base and alcohol groups of the sulfonates, are different depending on stabilization of the carbanion precursors and structure of the carbonyl substrates. The practical synthetic guide is supplemented with a discussion of the mechanism, based on reactivity studies of intermediates and identification of side-products.
- Górski, Bartosz,Basiak, Dariusz,Talko, Alicja,Basak, Tymoteusz,Mazurek, Tomasz,Barbasiewicz, Micha?
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p. 1774 - 1784
(2018/04/27)
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- ALKANESULFONYLATION.XX. CATALYSIS OF THE PHENOLYSIS OF ALKANESULFONYL CHLORIDES IN PROTON-INERT MEDIA CATALYZED BY PYRIDINE BASES. THE EFFECT OF THE SUBSTRATE STRUCTURE
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The kinetics of the reaction of methane-, ethane-, propane-, 1-methylmethane-, and cyclohexanesulfonyl chlorides and also of substituted phenylmethanesulfonyl chlorides with phenol in the presence of pyridine in chlorobenzene at 303 K were studied by GLC
- Skrypnik, Yu. G.,Lyashchuk, S. N.
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p. 695 - 700
(2007/10/02)
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- ALKANESULFONATION REACTIONS. XIX. STUDY OF THE COMPETING MECHANISMS IN THE PYRIDINE-CATALYZED PHEN-OLYSIS OF BENZYLSULFONYL CHLORIDE. EFFECT OF REAGENT STRUCTURE
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Gas-liquid chromatography and potentiometric titration were used for the first study of the kinetics of the reaction of a broad range of substituted phenols XC6H4OH with benzylsulfonyl chloride in the presence of pyridine in chlorobenzene at 30 deg C.This reaction proceeds through two competing pathways, namely, elimination-addition (A) and general base catalysis (B).The mesomeric and induction effects of the substituent X were quantitatively determined for pathway B and the predominance of the inductive effect was demonstrated (ρ0 0.828, ρ+ 0.214).The criteria were determined for realization of the competing pathways depending on the phenol structure, including steric hindered structures.The effect of reagent-intermediate orientation was determined in the case of pathway A.
- Skrypnik, Yu. G.,Lyahchuk, S. N.,Bezrodnyi, V. P.,Kalmykova, N. Yu.
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p. 1157 - 1164
(2007/10/02)
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- ALKANESULFONYLATION REACTIONS. XVI. EFFECT OF THE STRUCTURE OF PYRIDINE BASES ON THE RATE AND MECHANISM OF THE ALKANESULFONYLATION OF PHENOLS
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The effect of the structure of puridine bases on the phenolysis of phenylmethanesulfonyl chloride in chlorobenzene at 30 deg C was studied.The reaction takes place in two directions (elimination-addition EN-AdN and nucleophilic subst
- Lyashchuk, S. N.,Bezrodnyi, V. P.,Skrypnik, Yu. G.
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p. 698 - 704
(2007/10/02)
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- ALKANESULFONYLATION REACTIONS. X. EFFECT OF THE STRUCTURE OF THE ALKANESULFONYL HALIDE ON THE FORMATION OF PHENYLALKANESULFONATES CATALYZED BY TRIETHYLAMINE
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The kinetics of the reactions of methane-, propane-, isopropane-, cyclohexane, and phenylmethanesulfonyl chlorides and propanesulfonyl bromide with phenol in the presence of triethylamine in benzene at 30 deg C were investigated by GLC and potentiometric
- Bezrodnyi, V. P.,Skrypnik, Yu. G.
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p. 1660 - 1665
(2007/10/02)
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