【作者】 何霆；

【导师】 梁永民；

【作者基本信息】 兰州大学 ， 有机化学， 2013， 硕士

【摘要】 金、铂是位于第六周期的过渡金属元素,它们除了具有过渡金属的通性以外,还含有特殊的Lewis酸性,我们又将其称为π酸性。它们的这种性质使得其对不饱和键尤其是炔键具有独特的活化能力。近年来,金铂作为催化剂的催化反应被越来越多的化学家们所重视。多取代呋喃是天然产物和药物分子中的一种重要的结构单元,同时它也是合成化学中合成复杂的天然以及非天然产物的重要中间体,因此,合成呋喃环骨架一直是有机化学方法学中的研究热点。我们课题组在金、铂催化炔基活化方面做了大量研究,本论文在此基础上,针对金、铂催化的共轭烯炔羰基化合物与烯烃环加成合成环戊烷并呋喃环结构进行了初步的探索,主要通过以下两个方面开展了研究工作。1.我们以2-苯乙烯基-4苯基-3-丁炔醛为底物,通过简单的铂催化剂活化炔键,诱发分子内的羰基亲核进攻形成呋喃环结构,同时通过富电子的烯烃亲核进攻碳正离子,彼此发生[3+2]环加成高选择性的生成了环戊烷并[b]呋喃,通过改变官能团进一步研究发现该反应具有优秀的选择性和产率以及较好的适用性。2.在铂催化共轭烯炔醛与烯烃环化过程中,我们发现共轭烯炔酮与烯烃之间并没有发生类似反应生成环戊烷并[b]呋喃的结构,而是生成了一种三取代的呋喃结构,在进一步的研究探索过程中,我们发现金催化剂能够在温和的条件下迅速将2-苯乙烯基-4苯基-3-丁炔苯酮与烯烃催化串联环化形成环戊烷并[c]呋喃结构,并且得到了优秀的产率以及较好的适用性。更多还原

【Abstract】 Gold and platinum are the6th period later transition elements, they not only act as transition metals, but also as lewis acids, which are also called π-acid. The individual lewis acids show high activity to the alkyne group. In recent years, the reactions via gold, platinum-catalyzed have drawn much attention of chemists.The synthesis of highly substituted furans has attracted tremendous interest for several decades, resulting from both the importance of the five-memembered heterocycles in natural products and pharmaceuticals and the uniqueness as a useful intermediates in total syntheses. Therefore, the atom-economical and region-defined approaches to synthesis of highly substituted furans have particularly held our attention.Our groups have many studies on gold and platinum catalysis, this thesis is concemed with studies on the reaction of conjugated enyne carbonyl compouds and alkenes catalyzed by gold and platinum. It is divided into two parts as follows:1. We choose2-(1-alkynyl)-3-aryl-2-propenals as subtrates, the oxygen of the carbonyl group, used as a nucleophile, attacks alkynes which activated by platinum to form an oxonium ion intermediate, which subsequently isomerizes to a furan carbocation. Then, the nucleophilic attack of electron-rich olefins to the carbocation and [3+2] cyclization occurs subsequently to obtain polysubstituted4H-cyclopenta[b]furans. The reaction shows a good to excellent yield. and high chemo-and regioselectivity.2. The substrate2-benzylidene-1,4-diphenylbut-3-yn-l-one and ethene-1,1-diyldibenzene can not react to the4H-cyclopenta[b]furans catalyzed by platinum. To our surprise, they can be cyclizated to obtain a4H-cyclopenta[c]furans in the presence of gold. The reaction shows good yield and regioselectivity.更多还原