Recyclable Supported Carbene Catalysts for High-Yielding Self-Condensation of Furaldehydes into C<sub>10</sub> and C<sub>12</sub> Furoins
作者:Lu Wang、Eugene Y.-X. Chen
DOI:10.1021/acscatal.5b01410
日期:2015.11.6
dodecyl) on the azolium nitrogen atom, upon activation with a suitable base to generate the corresponding N-heterocyclic carbene (NHC) catalyst, are found to be far more effective catalysts for furaldehyde self-coupling reactions than the analogous catalysts carrying a short-chain alkyl substituent (i.e., C1 methyl). Thus, supported NHC catalysts generated in situ from Silica-g-[BI]-C12 or PS-g-[BI]-C12-benzyl/base
已开发出两种高效且可循环利用的异质氮鎓催化剂体系,其中一种接枝(g)到无机氧化物(二氧化硅)上,另一种接枝到有机聚合物[Merrifield肽或氯甲基化聚苯乙烯(PS)树脂]上,并用于催化定量自身糠醛和5-羟甲基糠醛(HMF)的C-偶合(uppolung缩合)反应分别进入C 10和C 12糠醛。带有长链烷基取代基(即C 12)的负载的苯并咪唑鎓盐[[BI])偶氮氮原子上的十二烷基)经适当的碱活化生成相应的N-杂环卡宾(NHC)催化剂后,发现它比带有短链的类似催化剂更有效地进行呋喃醛自偶联反应烷基取代基(即,C 1甲基)。因此,在原位产生支持NHC催化剂从二氧化硅-克- [BI] -C 12或PS-克- [BI] -C 12 -苄基/基得到Ç 10和C 12呋喃素的收率分别约为97%和94%。通过采用催化剂循环程序,其中包括用碱活化预催化剂以生成NHC催化剂,催化将呋喃醛转化为呋喃酮,以及通