Palladium-Catalyzed Diastereo- and Enantioselective [3+2] Cycloaddition of Vinylcyclopropanes with Azadienes: Efficient Access to Chiral Spirocycles
Palladium-Catalyzed Diastereo- and Enantioselective [3+2] Cycloaddition of Vinylcyclopropanes with Azadienes: Efficient Access to Chiral Spirocycles
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钯催化的非对映选择性和对映选择性 [3 2] 乙烯基环丙烷与氮杂二烯的环加成：有效获得手性螺环
DOI：
10.1021/acs.orglett.0c04062
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发表时间：
2021-01-27
期刊：
影响因子：
5.2
通讯作者：
Li, Xiaoxun
中科院分区：
文献类型：
--
作者：
Liu, Kai;Yang, Jianfeng;Li, Xiaoxun
苯并呋喃衍生的氮杂二烯（benzofuran derived azadienes，BDAs）作为四原子配体在过渡金属催化的环加成反应中得到了广泛的应用，而利用其作为双原子配体的反应活性来构建螺环的研究还不多见。本文首次报道了钯（0）催化的乙烯基环丙烷（VCPs）和BDA的非对映和对映选择性[3 + 2]成环反应。该转化的特征在于具有广泛的底物范围（31个实例），允许在温和的反应条件下以良好的产率容易地获得具有季立体中心的多种对映体富集的螺环，具有优异的区域选择性、非对映体选择性和对映体选择性（高达93%产率，>20：ldr，并且大多数> 99%ee）。此外，螺环产物可以有效地转化为结构复杂的三环[8.3.0.0（1，5）]-氮杂十三烷和三环[7.3.0.0（1，5）]-氮杂十二烷骨架。
Benzofuran-derived azadienes (BDAs) have been widely used as four-atom synthons in transition-metal-mediated cycloaddition reactions, while the exploitation of their reactivity as a two-atom unit to construct spirocycles is still underdeveloped. Herein, we reported the first palladium(0)-catalyzed diastereo- and enantioselective [3 + 2] annulation of vinylcyclopropanes (VCPs) and BDAs. This transformation is featured with a broad substrate scope (31 examples), allowing for facile access to a variety of enantioenriched spirocycles bearing a quaternary stereogenic center in good yields with excellent regio-, diastereo-, and enantioselectivities (up to 93% yield, >20:1 dr, and mostly >99% ee) under mild reaction conditions. Moreover, the spirocyclic products could be efficiently converted to structurally complex tricyclo[8.3.0.0(1,5)]-azatridecane and tricyclo[7.3.0.0(1,5)]-azadodecane skeletons.