Reactions of trimethylsilyl-derived iodohydrins with electron-rich π-systemsElectronic supplementary information (ESI) available: Additional results and experimental data, 1H NMR, 13C NMR and mass spectral data. See http://www.rsc.org/suppdata/p1/b1/b105233k/
作者:Eti Ishai、Sarit Shamai、Ben-Ami Feit
DOI:10.1039/b105233k
日期:2002.1.23
Reactions of trimethylsilyl-derived iodohydrins of the type R1R2CHâCH(I)OTMS, with electron-rich olefins, and the effects of certain factors on these reactions, were studied. The trimethylsilyl-derived iodohydrins were obtained in situ by reacting R1R2CHâCHO (R1
= R2
= H; R1
= H, R2
= alkyl, phenyl) with TMSI. The corresponding trimethylsilyl enol ether derivatives (R1R2CCHâOTMS), and 1,1-diarylethylenes were the olefins used. Aldehydes of the type RCH2âCHO reacted smoothly in the presence of TMSI to yield the condensation product RCH2âCHC(R)âCHO. Both RCH(âCHCAr2)2 and the cyclic acetal 5 were obtained as main products of the RCHOâTMSIâCH2CAr2
reaction system, depending on the [RCHO] â¶ [TMSI] â¶ [CH2CAr2] concentration ratio. The mechanisms of formation for the various main products and by-products are discussed. TMSI substitutes, formed by reacting Me3SiCl with each of several Lewis acids, were also used.
研究了从三甲硅基衍生的碘醇R1R2CH-CH(I)OTMS与富电子烯烃的反应,以及某些因素对这些反应的影响。三甲硅基衍生的碘醇是通过R1R2CH-CHO(R1=R2=H;R1=H,R2=烷基、苯基)与TMSI反应在原位获得的。所用的烯烃是相应的三甲硅基烯醇醚衍生物(R1R2CCH-OTMS)和1,1-二芳基乙烯。在TMSI存在下,RCH2-CHO类型的醛顺利反应生成缩合产物RCH2-CHC(R)-CHO。RCHO-TMSI-CH2CAr2反应体系主要生成RCH(-CHCAr2)2和环状缩醛5,这取决于[RCHO]:[TMSI]:[CH2CAr2]的浓度比。讨论了各种主要产物和副产物的形成机理。还使用了通过Me3SiCl与几种Lewis酸反应形成的三甲硅基取代物。