膦催化的γ-官能化丁炔酸酯和 1C,3O-双亲核试剂的[3+2]环加成反应：高选择性试剂控制的多取代呋喃合成途径。
Phosphine-catalyzed [3+2] annulations of γ-functionalized butynoates and 1C,3O-bisnucleophiles: highly selective reagent-controlled pathways to polysubstituted furans.
机构信息
Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Meilong Road No. 130, Shanghai, 200237, China.
出版信息
Org Lett. 2011 Jun 17;13(12):3068-71. doi: 10.1021/ol200940a. Epub 2011 May 16.
In this paper, a reagent-controlled [3+2] annulation of γ-functionalized butynoates 1 and 1C,3O-bisnucleophiles 2 is reported, which leads to three distinct furan skeletons 3-5. A PPh(3) catalyst preferentially attached the β-position of 1a, facilitating α-addition to furnish Type I annulations. With the assistance of Ag(2)O, Type II annulations were achieved via selective γ-substitution. In the absence of the PPh(3) catalyst, the reagent Cs(2)CO(3) promoted β-addition to realize Type III annulations.
本文报道了一种试剂控制的γ-官能化丁炔酸酯 1 和 1C,3O-双亲核试剂 2 的[3+2]环加成反应，生成了三个不同的呋喃骨架 3-5。PPh(3)催化剂优先与 1a 的β位结合，有利于α加成，生成 I 型环加成产物。在 Ag(2)O 的协助下，通过选择性γ取代实现了 II 型环加成。在没有 PPh(3)催化剂的情况下，试剂 Cs(2)CO(3)促进β加成，实现了 III 型环加成。
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