- Electron-transfer processes. 43. Attack of alkyl radicals upon 1-alkenyl and 1-alkynyl derivatives of tin and mercury
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Alkyl radicals, obtained by reaction of Bu3Sn? or ClHg? with alkylmercury halides, will undergo regioselective and in some cases stereospecific substitution by a free radical chain addition-elimination mechanism with 1-alkenylstannanes or -mercurials. The chain reaction is also observed for 1-alkynyl derivatives and in the photostimulated demercuration of mixed alkyl and 1-alkenyl- or 1-alkynylmercurials. Chain propagation with alkyl radical formation is also observed to occur in the reactions of β-eliminated ClHg? with Grignard reagents in PhH-THF solution. In competitive reactions of Bu3Sn? or ClHg? with pairs of alkylmercury chlorides, it is observed that a tert-butylmercurial is >1000 times more reactive than a n-butylmercurial, suggesting a concerted dissociate electron-transfer process not involving the intermediacy of RHg? species.
- Russell, Glen A.,Ngoviwatchai, Preecha,Tashtoush, Hasan I.
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p. 696 - 702
(2008/10/08)
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- DIRECT TRANSFER OF ALIPHATIC AND AROMATIC SUBSTITUENTS FROM ORGANOSILATRANES TO MERCURY(II) SPECIES
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The relative reaction rates of several silatranes (derivatives of 2,8,9-trioxa-5-aza-1-silatricyclo1,5>undecane) and HgCl2 in acetone-d6 to yield the corresponding organomercury compound are of the order of e.g., 5 * 10-1 1 mol-1 sec-1 or slightly less, a rate that is unexpectedly high compared to the essentially inert parent organotrialkoxysilanes.Thus, the apical Si-C bond of the silatrane is extraordinarily susceptible to direct electrophilic attack by mercury(II).The rates decrease in the order CH2=CH, C6H5, p-ClC6H4 > CH3 > CH3CH2, CH3CH2CH2 > C6H11, ClCH2, Cl2CH, CH3CH2O.The effects of varying the solvent and the counterions are noted, and the probable mechanism is discussed.
- Nies, J. Dirk,Bellama, Jon M.,Ben-Zvi, Nava
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p. 315 - 320
(2007/10/02)
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