- New simple route to allylstannanes by zinc-mediated coupling of allyl bromides with Bu3SnCl or Bu2SnCl2 in an H2O (NH4Cl)/THF medium
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A new zinc-mediated coupling reaction of allyl and allyl-like bromides with Bu3SnCl (1) or Bu2SnCl2 (2), performed in H2O (NH4Cl)/THF medium, represents an easy route to the following organostannanes: Bu3SnCH2CH=CH2 (3) and Bu2Sn(CH2CH=CH2)2 (4), Bu3Sn(C4H7) (5) and Bu2Sn(C4H7)2 (6) (where C4H7 stands for trans-crotyl, cis-crotyl, or α-methylallyl), and Bu3SnCH=C=CH2 (7). This striking one-pot procedure successfully improves the already general routes where Grignard or other conventional organometallic reagents are used.
- Carofiglio, Tommaso,Marton, Daniele,Tagliavini, Giuseppe
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- METHOD FOR PRODUCING 14 GROUP METAL LITHIUM COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for quantitatively producing a group 14 metal lithium compound under a mild condition. SOLUTION: The method for producing a group 14 metal lithium compound represented by formula (4): R4-nMLin comprises reacting a compound represented by formula (1): R4-nMXn and lithium in the presence of a polycyclic aromatic compound represented by formula (2) or formula (3). [In formula (1) and formula (2), R is a hydrocarbon group; M is a metal atom selected from Si, Ge and Sn; X is a halogen atom or R3M- (R and M are the same as mentioned above); and n is 1 or 2] and [R1 is H or a hydrocarbon group; and m is an integer of 0 to 5.] SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0070
(2016/10/31)
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- A novel mode of access to polyfunctional organotin compounds and their reactivity in Stille cross-coupling reaction
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Mono-, di-, tri- and tetra-functional organotin compounds were easily prepared in a sonicated Barbier reaction using ultrasound technology via coupling reaction of organo halides with tin halides (Bu3SnCl, Bu2SnCl2, BuSnCl
- Lamandé-Langle, Sandrine,Abarbri, Mohamed,Thibonnet, Jér?me,Duchêne, Alain
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p. 2368 - 2374
(2009/09/30)
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- On the use of mixtures of organotin species for catalytic enantioselective ketone allylation - A detective story
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In the presence of enantiopure MTBH2 (monothiobinaphthol, 2-hydroxy-2′mercapto-1,1′-binaphthyl; 0.2 eq.) quantitative allylation of ArC(=O)Me takes place with impure Sn(CH2CH=CH2)4 (prepared from allyl chloride, air-oxidised magnesium and SnCl4) to yield tert-homoallylic alcohols in 85-92% ee. In the same process highly purified, or commercial, Sn(CH2CH=CH2)4 yields material of only 35-50% ee. The origin of these effects is the presence of small amounts of the compounds, EtSn(CH2CH=CH2)3, ClSn(CH2CH=CH2)3 ClSnEt(CH2CH=CH2)2 in the tetraallyltin sample and the presence of traces of water (which inhibits achiral background reactions). All the triallyl and diallyl species enhance the stereoselectivity in the catalytic allylation reaction, the chlorides more so than the ethyl compound. Hydrolysis of ClSnEt(CH2CH=CH2)2 affords crystallographically characterised Sn4(μ3-O)(μ2-Cl)2 Cl2Et4(CH2CH=CH2)4. Reaction of this latter compound with MTBH2 leads to the most potent catalyst.
- Cunningham, Anthony,Mokal-Parekh, Vijaya,Wilson, Claire,Woodward, Simon
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p. 741 - 748
(2007/10/03)
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- Wurtz-type reductive coupling reaction of allyl bromides and haloorganotins in cosolvent/H2O(NH4Cl)/Zn media as a route to allylstannanes and hexaaryldistannanes
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Twenty-one allylstannanes have been prepared via a simple Wurtz-type coupling reaction of allyl bromides and R3SnX compounds (R = Me, Et, Pr, Bu, Ph; X = Cl, I, OH), Bu2SnCl2, and (Bu2SnCl)2O in cosolvent/H2O (NH4Cl saturated) media under the mediation of zinc powder. Also R3SnSnR3 compounds (R = Ph, p- and m-Tol) have been prepared via coupling of triaryltin chlorides. The stereochemical course of the reaction between R3SnCl and (C4H7)Br (C4H7 = α-methylallyl, trans- and cis-crotyl) has been extensively studied. Two distinct reactions are involved in the overall process: (i) the coupling reaction, which gives rise stereoselectively to the sole R3SnCH(CH3)CH=CH2 (α-isomer), and (ii) the subsequent isomerization of the α-isomer furnishing mixtures of (α, trans, cis)-isomers. The occurrence of reaction ii depends upon the nature either of the R group or the employed cosolvent. In cyclohexane, the α-isomer is exclusively obtained with R = Bu, while with R = Me, Et, and Pr it is found as a major component in the ternary isomeric mixture. In tetrahydrofuran, 2-propanol, acetonitrile, and pyridine, the isomerization occurs to an extent which depends on the polarity and the coordinating ability of the cosolvent itself. The observed stereoselection has been hypothesized to occur through one-electron transfer from the zinc metal to the (C4H7)Br to form stereoselectively an adsorbed CH2=CHCH(CH3)Br?-Zn?+ radical ion which is trapped by the R3SnCl reactant to form the α-isomer. Similarly, ditin compounds are thought to be formed by interaction of R3SnCl?-Zn?+ radical ions with R3SnCl molecules.
- Von Gyldenfeldt, Friederike,Marton, Daniele,Tagliavini, Giuseppe
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p. 906 - 913
(2008/10/08)
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- The effect of ligands, solvent and temperature on the reactions of allyltin(IV) compounds with singlet oxygen
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The reaction of singlet oxygen with a variety of allyltin compounds CH2=CHCH2SnR3 (R3 = Me3, Bu3, allyl3, (cyclo-C6H11)3, Ph3, allylBu2, Bu2Cl, Bu2OAc, allylCl2, allylCl2bipy) has been investigated, and the allylperoxytin compounds, 3-stannylallyl hydroperoxides, and 4-stannyl-1,2-dioxolanes which result from M-ene, H-ene and cycloaddition processes, respectively, have been identified by NMR spectroscopy.As the tin centre becomes more electropositive, as indicated by the 13C NMR shift of the allylic CH2 group, the proportion of the M-ene reaction increases, and when δCH2 is above about 23.7, the allylperoxytin compound is the only product.An exception to this rule is tetraallyltin, δCH2 16.13, which similarly shows only the M-ene reaction.This is tentatively ascribed to the special effect of hyperconjugation between the C-Sn ?-bond and the remaining ?-systems.A polar solvent favours the M-ene reaction.The cycloaddition reaction is favoured by low temperature, and at -70 deg C in a non-polar solvent it may become the major route.Diallylmercury and allylmercury chloride react with singlet oxygen to show only the M-ene reaction, but also undergo extensive photosensitized decomposition.With 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD), allylmercury chloride shows only the M-ene reaction.
- Dang, H.-S.,Davies, A. G.
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p. 287 - 298
(2007/10/02)
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