- Reactivity of carbon dioxide with n-butyl(phenoxy)-,(alkoxy)-, and (oxo)stannanes: insight into dimethyl carbonate synthesis
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The CO2 insertion into Sn-O bonds of a series of butyl(phenoxy)-, (alkoxy)-, and (oxo)-stannanes has been investigated. The tributyl derivatives Bu3SnOR (2a, R = Me; 3a, R = iPr; 4a, R = tBu; 5a, R = SnBu3)1 give quantitatively Bu3Sn(OCO2R), 2b-5b; the analogous tributylphenoxystannane, 1, is less reactive. For the dibutyl series, Bu2Sn(OR)2, steric effects of tBu groups in OR (8a) suppress carbonation under atmospheric pressure. With R = Me (6a) or R = iPr (7a), only one Sn-OR bond reacts, resulting in Bu2Sn(OR)(OCO2R), 6b or 7b. Treating 6a with 2-propanol affords under CO2 the mixed compound Bu2Sn(OMe)-(OCO2iPr), selectively. Facile deinsertion of CO2 is a common property of all compounds, occurring more readily in the dibutyl series. The stoichiometric transformation of the carbonato ligand in 2b, 5b, or 6b to dimethyl carbonate (DMC) on reaction with MeI requires nucleophilic assistance by F- to proceed. In the presence of MeOH, 2b and 5b are almost inactive for DMC formation, in contrast with 6b. The best yield is obtained under supercritical CO2-methanol conditions.
- Ballivet-Tkatchenko,Douteau,Stutzmann
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- A new method for the synthesis of stannyl ethers by acid-catalyzed reaction of alcohols with allyltributylstannane
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Stannyl ethers are prepared by triflic acid-catalyzed reaction of alcohols with tributylstannane or allyltributylstannane at room temperature. The stannyl ethers thus prepared can be successfully used for the β-bromogycoside-mediated glycosylation reactions.
- Yamago, Shigeru,Yamada, Takeshi,Nishimura, Ryuji,Ito, Hiroki,Mino, Yosuke,Yoshida, Jun-Ichi
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- Effect of tributyltin alkoxides chain length on the ring-opening polymerization of ε-caprolactone: Kinetics studies by non-isothermal DSC
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The kinetics of ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) initiated by 1.0 mol% of the tributyltin alkoxides (Bu3SnOR; R = Me, Et, nPr and nBu) was investigated by non-isothermal DSC technique. The DSC curves showed the depende
- Limwanich, Wanich,Khunmanee, Sureerat,Kungwan, Nawee,Punyodom, Winita,Meepowpan, Puttinan
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- Tin-Catalyzed Synthesis of 5-Substituted 1H-Tetrazoles from Nitriles: Homogeneous and Heterogeneous Procedures
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The preparation of 5-substituted 1H-tetrazoles was efficiently achieved by reaction of trimethylsilylazide with nitriles using a triorganotin alkoxide precatalyst. The reaction mechanism was first investigated using a homogeneous tributyltin derivative and was explored through experimental investigations and DFT calculations. A heterogeneous version was then developed using a polymer-supported organotin alkoxide and afforded an efficient method for the preparation of tetrazoles in high yields with an easy work-up and a residual tin concentration in the desired products compatible for pharmaceutical applications (less than 10 ppm). (Figure presented.).
- Chrétien, Jean-Mathieu,Kerric, Gaelle,Zammattio, Fran?oise,Galland, Nicolas,Paris, Michael,Quintard, Jean-Paul,Le Grognec, Erwan
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supporting information
p. 747 - 757
(2019/01/04)
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- TRANSPOSITION DES OXIRANNES-ETHANOLS PAR L'INTERMEDIAIRE D'ALCOXYETAINS
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Oxiraneethoxytributyltins prepared from the corresponding oxiraneethanols, on heating at 200 deg C gave, after demetalation with isophthalic acid, 2-oxetanemethanols and/or 3-oxolanols.As appears from about thirty rearrangements the choice between oxetane and oxolane formation is dependent on: (1) the relative degree of substitution of the oxirane ring; cyclization occuring predominantly at the more substituted carbon; and (2) the configuration of the oxirane ring, when both its ends are equally substituted; cis form being more suitable for genaration of the smaller ring.The reaction is shown to proceed with inversion of configuration at the site of oxygen attack.The results of attempts to perform the rearrangement in dilute-phase or throught alkaline metal alkoxides in various media support the conclusion that there is a large contribution by electrophilic assistance to the oxirane ring opening.Such assistance can be efficiently provided by a tin atom in a push-pull mechanism which accomodates all the facts.The present method of oxiraneethanol rearrangement may offer a convenient route to functional oxetanes.
- Bats, J. -P.,Moulines, J.,Picard, P.,Leclercq, D.
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p. 2139 - 2146
(2007/10/02)
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