Oxygen Atom Transfer as Key To Reverse Regioselectivity in the Gold(I)-Catalyzed Generation of Aminooxazoles from Ynamides
作者:Dmitry P. Zimin、Dmitry V. Dar’in、Vadim Yu. Kukushkin、Alexey Yu. Dubovtsev
DOI:10.1021/acs.joc.0c02584
日期:2021.1.15
We report on gold(I)-catalyzed oxidative annulation involving ynamides, nitriles, and 2,3-dichloropyridine N-oxide. The application of 2,3-dichloropyridine N-oxide as an oxygen atom transfer reagent reverses the regioselectivity to give 5-amino-1,3-oxazoles, in comparison with the previously reported syntheses of aminooxazoles based on gold-catalyzed nitrene transfers to ynamides to furnish 4-amino-1
我们报道了金(I)催化的涉及酰胺,腈和2,3-二氯吡啶N-氧化物的氧化环化反应。与以前报道的基于金催化的将腈转化为酰胺的氨基恶唑合成方法相比,使用2,3-二氯吡啶N-氧化物作为氧原子转移试剂可以逆转区域选择性,从而生成5-氨基-1,3-恶唑提供4-氨基-1,3-恶唑。发达的氧原子转移方法可生成在恶唑环第五位上包含各种磺酰基保护的烷基氨基的1,3-恶唑(29例;产率高达88%)。另外,使用N取代的腈,即氰胺,导致容易获得的难以获得的2,5-二氨基恶唑。该方法对于广泛范围的乙酰胺或腈是可行的,并且可以以克为单位进行。