Reaction Progress Kinetics Analysis of 1,3-Disiloxanediols as Hydrogen-Bonding Catalysts
Reaction Progress Kinetics Analysis of 1,3-Disiloxanediols as Hydrogen-Bonding Catalysts
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DOI：
10.1021/acs.joc.7b00875
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发表时间：
2017-07-07
影响因子：
3.6
通讯作者：
Franz, Annaliese K.
中科院分区：
文献类型：
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作者：
Diemoz, Kayla M.;Hein, Jason E.;Franz, Annaliese K.
1,3-二硅氧烷二醇是有效的氢键催化剂，相对于硅烷二醇和三芳基硅烷醇，其活性更高。一系列 1,3-二硅氧烷二醇（包括萘基取代的和不对称的硅氧烷）的催化活性已通过吲哚与反式-β-硝基苯乙烯的 Friedel Crafts 加成进行了量化，并与其他硅烷醇和硫脲催化剂进行了比较。使用反应进程动力学分析 (RPKA) 进行了深入的动力学研究，以探讨 1,3-二硅氧烷二醇的催化剂行为。数据证实，在所研究的所有浓度下，二硅氧烷二醇催化的加成反应在催化剂中是一级反应，没有催化剂自缔合的证据。 1,3-二硅氧烷二醇被证明是稳健且可回收的催化剂，在反应条件下不会失活。没有观察到产物抑制，并且与含硝基添加剂的竞争性结合研究表明，1,3-二硅氧烷二醇与硝基的结合较弱，但具有强烈的催化活性。
1,3-Disiloxanediols are effective hydrogen-bonding catalysts that exhibit enhanced activity relative to silanediols and triarylsilanols. The catalytic activity for a series of 1,3-disiloxanediols, including naphthyl-substituted and unsymmetrical siloxanes, has been quantified and compared relative to other silanol and thiourea catalysts using the Friedel Crafts addition of indole to trans-beta-lnitrostyrene. An in-depth kinetic study using reaction progress kinetic analysis (RPKA) has been performed to probe the catalyst behavior of 1,3-disiloxanediols. The data confirm that the disiloxanediol-catalyzed addition reaction is first order in catalyst over all concentrations studied with no evidence of catalyst self-association. 1,3-Disiloxanediols proved to be robust and recoverable catalysts with no deactivation under reaction conditions. No product inhibition is observed, and competitive binding studies with nitro-containing additives suggest that 1,3-disiloxanediols bind weakly to nitro groups but are strongly activating for catalysis.