Direct Asymmetric α‐Selective Mannich Reaction of β,γ‐Unsaturated Ketones with Cyclic α‐Imino Ester: Divergent Synthesis of Cyclocanaline and Tetrahydro Pyridazinone Derivatives
作者:Yu‐Huan Geng、Yuan‐Zhao Hua、Shi‐Kun Jia、Min‐Can Wang
DOI:10.1002/chem.202100284
日期:2021.3.17
The first regio‐, diastereo‐, and enantioselective direct Mannich reaction of β,γ,‐unsaturated ketones with benzoxazinone cyclic imines was enabled by Lewis acid/Brønsted base cooperative catalysis. The dinuclear zinc complex catalyzed the reaction of a broad range of β,γ‐unsaturated ketones to proceed at the α‐site exclusively, leading to corresponding adducts with two consecutive tertiary carbon
路易斯酸/布朗斯台德碱协同催化作用使β,γ-不饱和酮与苯并恶嗪酮环状亚胺进行了第一个区域,非对映和对映选择性的直接曼尼希反应。双核锌络合物催化广泛的β,γ-不饱和酮反应仅在α位进行,从而导致相应的加合物具有两个连续的叔碳立体中心,其非对映异构体比例高达> 20:1,并且通常具有对映选择性在90–99%ee范围内。这些产物被用作一般中间体,用于合成多取代的环茶碱,四氢哒嗪酮和4 H-呋喃[2,3- b ] [1,4]苯并恶嗪衍生物。