Gold(I)-catalysed tandem cyclization of propargyl acetals and alkynes
作者:Huey-San Melanie Siah、Morten Christian Hogsnes、Naseem Iqbal、Anne Fiksdahl
DOI:10.1016/j.tet.2015.12.080
日期:2016.2
To expand the understanding of the chemistry of propargyl acetals, their gold(I) catalysed cycloaddition reactions with alkynes have been investigated. We hereby report a novel tandem reaction that allows the construction of a new type of polysubstituted and highly functionalised bicyclic pentalene compounds, 2,6a-dimethoxy-3a-methyl-1,4,5-triphenyl-1,3a,4,6a-tetrahydropentalenes, with four stereogenic
Gold(I)-catalysed [3+3] cycloaddition of propargyl acetals and nitrones
作者:Sigvart Evjen、Anne Fiksdahl
DOI:10.1016/j.tet.2016.04.058
日期:2016.6
the understanding of the gold(I) catalysis chemistry of propargyl acetals, a gold(I) catalysed [3+3] cycloaddition reaction of propargyl acetals with nitrones has been studied. A series of 5-methoxy-3,6-dihydro-2H-1,2-oxazine products with two stereogenic centres were obtained in a cis-stereoselective manner. The formal [3+3] cycloaddition reaction is supposed to go through O-nucleophilic attack of
在我们的一系列研究中,为加深对炔丙基缩醛的金(I)催化化学的理解,研究了金(I)催化的炔丙基缩醛与硝酮的[3 + 3]环加成反应。以顺式-立体选择性的方式获得了具有两个立体生成中心的一系列5-甲氧基-3,6-二氢-2 H -1,2-恶嗪产物。正式的[3 + 3]环加成反应应该经过硝酮对C的O-亲核攻击由炔丙基缩醛产生的金络合物的1位,随后进行最终的闭环。硝酮的另一种C3氧化作用可提供醛产物,并且代表了竞争途径。为了证明反应的潜力和局限性,讨论了环加成反应的化学选择性。
Gold(I)-Catalyzed Benz[<i>c</i>]azepin-4-ol Synthesis by Intermolecular [5 + 2] Cycloaddition
作者:Naseem Iqbal、Anne Fiksdahl
DOI:10.1021/jo401075n
日期:2013.8.16
N-heterocyclic azepine products is presented. A number of benz[c]azepin-4-ol products were readily prepared in one step from easily accessible phenylpropargyl acetals and benzaldimine substrates in the presence of a gold(I) catalyst. A direct one-pot procedure from the propargyl and the respective aldehyde and amine substrates was successful as well. The reaction to access the benzofused azepines could be
介绍了一种金(I)催化的分子间缩甲醛[2 + 5]环加成反应,用于制备苯并稠合的N-杂环氮杂产物。在金(I)催化剂的存在下,很容易从容易获得的苯基炔丙基缩醛和苯甲二胺底物中一步制备许多苯并[ a ]氮杂-4-醇产物。炔丙基以及相应的醛和胺底物的直接一锅法也很成功。可以通过级联反应(包括亲核性苯扎二胺N)合理化获得苯并稠合氮杂物的反应-从炔丙基缩醛生成的高反应性苯基炔丙基-金(I)类胡萝卜素复合物上进行攻击。随后的脱脂步骤通过与醛亚胺部分的分子内Pictet-Spengler型反应,通过1,7-电环化促进环的闭合。
Gold(I)-Catalysed Azepine Synthesis from Propargyl Acetals and Aryl Azides
作者:Sigvart Evjen、Anne Fiksdahl
DOI:10.1002/ejoc.201600319
日期:2016.6
Gold(I)-catalysed reactions of phenylpropargyl acetals and aryl azides gave trans-3,6-methoxy-1,4,5-triaryl-4,5-dihydro-azepine products (78–94 %) in a highly diastereoselective manner. Two units of propargyl acetal and one unit of aryl azide are incorporated into the azepine product. The reaction proceeds by a sequential two-step pathway via an activated Z-2-methoxy vinyl imine intermediate, with