- Reactions of Trialkylstannane Anions R3Sn- with Arylstannanes ArSnR'3
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The reactions of trialkylstannane anions R3Sn- with arylstannanes ArSnR'3 have been investigated; trialkylstannane anions with arylstannanes at 50 deg C gave substitution products ArSnR3 in good yields.Most of these substitution products are diverted to r
- Mochida, Kunio
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p. 3299 - 3306
(2007/10/02)
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- DIE CHEMIE DER SCHWEREN CARBEN-ANALOGEN R2M, M=Si, Ge, Sn. X. 7-SILA-NORBORNADIENE: REAKTIONEN MIT HALOGENEN UND THERMOLYSE IN GEGENWART VON METALLORGANISCHEN ODER ORGANISCHEN HALOGENIDEN
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The 7-sila-norbornadienes (I-IV) react rapidly with halogens at -20 to +20 deg C to yield Me2SiHal2 (Hal=Cl, Br, I) and the naphthalene or benzene derivatives (V-VIII).Bromine in CCl4 at 0 deg C, however, caused surprising rearrangement in I giving the 2-bromosilylated naphthalene (IX), since an attack at the alkene group seemed to be preferred.Methylation and methoxylation of IX gave respectively X and XI.Careful hydrolysis of IX yielded the disiloxane XII.Insertions of Me2Si into the Si-Hal, Si-H, Si-C, or Sn-C bonds were not observed at 160-200 deg C, whereas insertions into Sn-Cl or Sn-H bonds occurred smoothly via a one-step mechanism.Halogen is abstracted from different C-Hal bonds leading to Me2SiHal2 and sometimes to Me4Si2Hal2.The degradation of the silylene precursors in these cases is always first order and resembles that of spontaneous thermolysis.
- Appler, Hubertus,Neumann, Wilhelm P.
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p. 247 - 260
(2007/10/02)
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- MECHANISTIC STUDIES ON DECOMPOSITION OF TRIALKYLSTANNYLLITHIUMS
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The fast decomposition of trialkylstannyllithiums, R3SnLi (R=Me, Et and Bu), in the presence of hexaalkyldistannanes, R3SnSnR3, was observed, and its mechanism was investigated kinetically.Partial dissociation of R3SnLi into a complex in a solvent cage is suggested to occur in the initial step.The RLi in the complex can be trapped instantaneously by R3SnSnR3 to afford R4Sn and R3SnLi, and the counterpart R2Sn: by R3SnLi giving R3SnR2SnLi.The decomposition of R3SnLi followed first-order kinetics within 3.5 h, corresponding well to the rate of disappearance of R3SnSnR3 and of appearance of R4Sn.The partial dissociation rate constant (k1) of Me3SnLi into the complex was determined as 2.0*10-3 min-1.The values of k1 are about 100 times those of rate constants (k') for decomposition of R3SnLi in the absence of R3SnSnR3.Reformation of R3SnLi from the complex is highly significant.
- Kobayashi, Kazuko,Kawanisi, Mituyosi,Hitomi, Torazo,Kozima, Sinpei
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p. 299 - 311
(2007/10/02)
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