据报道,铝(I)和镁(I)化合物可用于应变亚烷基环丙烷的 CC σ 键活化。这些反应导致在单个位点 (Al) 或跨金属-金属键 (Mg-Mg) 将 CC σ-键正式添加到主族中心。机理研究表明,这些反应不是通过协同氧化加成发生,而是涉及逐步过程,其中底物与主族金属结合作为破坏 CC σ 键的 α- 或 β- 烷基迁移步骤的前体。这种机理理解用于开发亚烷基环丙烷的 CC σ 键的镁催化氢化硅烷化。
examples of an iron‐catalyzed three‐component synthesis of homoallylic boronates from regioselective union of bis(pinacolato)diboron, an alkenyl halide (bromide, chloride or fluoride), and an olefin are disclosed. Products that bear tertiary or quaternary carbon centers could be generated in up to 87 % yield as single regioisomers with complete retention of the olefin stereochemistry. With cyclopropylidene‐containing
Synthesis of DPPP- and DPPPEN-Type Bidentate Ligands by Ring-Opening Diphosphination of Methylene- and Vinylcyclopropanes under Visible-Light-Promoted Photoredox Catalysis
A ring-opening diphosphination of methylene- and vinylcyclopropanes with tetraaryldiphosphines (Ar2P-PAr2) has been developed to afford the corresponding 1,3-diphenylphosphinopropane- and 1,3-diphenylphosphinopentane-type bidentate ligands, respectively. The reaction proceeds under bromine cation-initiated, visible-light-promoted photoredox catalysis at ambient temperature. Owing to the ready availability
Formal (4+1) Cycloaddition of Methylenecyclopropanes with 7-Aryl-1,3,5-cycloheptatrienes by Triple Gold(I) Catalysis
作者:Yahui Wang、Michael E. Muratore、Zhouting Rong、Antonio M. Echavarren
DOI:10.1002/anie.201404029
日期:2014.12.15
7‐Aryl‐1,3,5‐cycloheptatrienes react intermolecularly with methylenecyclopropanes in a triple gold(I)‐catalyzed reaction to form cyclopentenes. The same formal (4+1) cycloaddition occurs with cyclobutenes. Other precursors of gold(I) carbenes can also be used as the C1 component of the cycloaddition.
intramolecular additions of pronucleophiles to methylenecyclopropanes proceeded smoothly in the presence of catalytic amounts of Pd(PPh3)4, affording hydrocarbonation products in good to high yields. The ringopening of methylenecyclopropanes mainly occurred at the distal position to the exomethylene. In some cases, proximal bond cleavage also took place. The mode of ringopening depended upon both the
Herein, we report on selectivity control in C–H activations with alkylidenecyclopropanes (ACPs) for the chemo-selective assembly of cyclopropanes or dienes. Thus, unprecedented rhodaelectro-catalyzed C–H activations were realized with diversely decorated ACPs with a wide substrate scope and electricity as the sole oxidant.