1,3-Dipolar Cycloaddition to the Fe−XC Fragment 18. Chemoselectivity in the Addition of Activated Alkynes across the Fe−OC Fragment vs the Fe−NC Fragment in Chelate (α-Imino ester)tricarbonyliron Complexes
作者:Ron Siebenlist、Mireille de Beurs、Nantko Feiken、Hans-Werner Frühauf、Kees Vrieze、Huub Kooijman、Nora Veldman、Miles T. Lakin、Anthony L. Spek
DOI:10.1021/om991027y
日期:2000.8.1
Fe(CO)3(R1NC(R2)C(R3)O) (R1 = alkyl, R2 = H, R3 = O-alkyl) (7a−j) react with dimethyl acetylenedicarboxylate (DMAD) via a 1,3-dipolar cycloaddition reaction to form four products as a result of cycloaddition to both the Fe−OC and the Fe−NC fragments. The main product is the Fe(CO)3(butenolide) complex (10), which results from cycloaddition to the Fe−OC fragment, indicating that this fragment is more reactive
原位制备螯合物Fe(CO)3(R 1 N C(R 2)C(R 3)O)(R 1 =烷基,R 2 = H,R 3 = O-烷基)(7a - j)反应乙炔基二羧酸二甲酯(DMAD)通过1,3-偶极环加成反应形成四个产物,这是由于Fe-O C和Fe-N C片段都被环加成的结果。主要产物是Fe(CO)3(丁烯内酯)络合物(10),它是由环加成到Fe-O C片段上而得到的,表明该片段比Fe-N C片段更具反应性。复合体图10,图11,图13和图15已通过光谱法(IR,1 H和13 C NMR,FD-质量)和元素分析来表征。通过单晶X射线衍射已经建立了所有四种类型的配合物(10d,11a,13c和15h)的分子结构。产物的形成和分布由R 1和R 3取代基决定。与活化程度较低的炔丙基丙酸甲酯(MP)的反应导致反应缓慢,仅导致Fe-O环加成C片段会根据提供的其他配体形成两种产物。吸收另外的CO配体导致Fe