Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan and.
Faculty of Science, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan.
Org Lett. 2021 May 21;23(10):3981-3985. doi: 10.1021/acs.orglett.1c01171. Epub 2021 May 12.
A gold(I) autotandem catalysis protocol is reported for the de novo synthesis of densely substituted pyrazolines and dihydropyridines from the corresponding imine derivatives in a highly regioselective fashion via a one-pot aza-enyne metathesis/6π-electrocyclization sequence. The substituents on the nitrogen atom of the imine perfectly control the reaction pathways from the pivotal 1-azabutadiene intermediate; thus, carbazates were converted into pyrazolines via 6π-electrocyclization of α,β-unsaturated hydrazones, while aryl imines provided dihydropyridines via 6π-electrocyclization of 3-azahexatrienes.
报道了一种金（I）自动串联催化策略，可通过一锅氮烯炔复分解/6π-电环化反应序列，从相应的亚胺衍生物出发，以高区域选择性方式从头合成高度取代的吡唑啉和二氢吡啶。亚胺氮原子上的取代基可完美控制关键的 1-氮杂丁二烯中间体的反应途径；因此，通过α,β-不饱和腙的 6π-电环化，将氨基甲酸酯转化为吡唑啉，而芳基亚胺则通过 3-氮杂己三烯的 6π-电环化生成二氢吡啶。
