The effect of the active site and substrate structure in preparation of substituted tetrahydropyrans via intramolecular cyclization
作者:Ondřej Veselý、Marek Živný、Martin Nigríni、Jan Veselý、Jiří Čejka
DOI:10.1016/j.cattod.2023.114465
日期:2024.3
electron-withdrawing groups have the opposite effect. Furthermore, the cyclization reaction also occurred on substrates containing different aromatic cycles. However, the conversion of a bulky substrate containing naphthyl group decreased due to mass transfer limitations. The catalytic performance of different types of zeolites with diverse acid sites was also examined. Brønsted acidic zeolites such as Al-BEA and Ga-BEA
取代四氢吡喃(THP)是重要的生物活性化合物和合成中间体。它们的普遍性和多样化的应用使它们成为合成有机化学的理想目标。目前THP合成的合成路线涉及均相催化剂,通常需要多个步骤并使用昂贵的重金属催化剂,这会带来环境问题。因此,需要寻找能够提高效率、生态友好性和成本效益的替代方法。本研究重点是通过取代 ( E )− 5-苯基戊-4-en的分子内环化来酸催化合成 THP。 -1-醇在沸石上作为非均相催化剂。该研究特别侧重于研究官能团以及底物尺寸对反应结果的影响。结果表明,给电子基团增强了反应物的转化率并提高了对THPs的选择性,而吸电子基团则具有相反的作用。此外,环化反应也发生在含有不同芳香环的底物上。然而,由于传质限制,含有萘基的大体积底物的转化率下降。还检查了具有不同酸位点的不同类型沸石的催化性能。Al-BEA 和 Ga-BEA 等布朗斯台德酸性沸石表现出良好的催化性能,对 THP 的选择性分别为