as a powerful strategy for organometallic catalysis, and yet electrocatalytic C−Hactivation is restricted to strongly N‐coordinating directing groups. The first example of electrocatalytic C−Hactivation by weak O‐coordination is presented, in which a versatileruthenium(II) carboxylate catalyst enables electrooxidative C−H/O−H functionalization for alkyne annulations in the absence of metal oxidants;
电催化已被认为是有机金属催化的有力策略,但是电催化CH活化仅限于强N配位的导向基团。给出了通过弱O配位进行电催化C-H活化的第一个例子,其中通用的羧酸钌(II)催化剂可在没有金属氧化剂的情况下实现炔烃环化的电氧化C / H / OH功能化。从而利用可持续的电力作为唯一的氧化剂。机械学的见解为简便的有机金属CH钌钌化和关键钌(0)中间体的有效电化学再氧化提供了有力的支持。
Cp*Ir<sup>III</sup>-Catalyzed Oxidative Coupling of Benzoic Acids with Alkynes
作者:Daniel A. Frasco、Cassandra P. Lilly、Paul D. Boyle、Elon A. Ison
DOI:10.1021/cs400656q
日期:2013.10.4
Cp*Ir(III) complexes have been shown to catalyze the oxidative coupling of benzoic acids with alkynes in methanol at 60 °C to form a variety of isocoumarins. The use of AgOAc as an oxidant was required to facilitate significant product formation. Alkyl alkynes were shown to be more reactive substrates than aryl alkynes, and a number of functional groups were tolerated on benzoic acid. Combined mechanistic
Aerobic oxidative CH functionalizations of weakly coordinating benzoic acids have been accomplished with versatile ruthenium(II) biscarboxylates under ambient oxygen or air. Mechanistic studies identified the key factors controlling the elementary step of the oxidation of the ruthenium(0) complex.
An intermolecular nickel-catalyzedaddition reaction has been developed where phthalic anhydrides react with alkynes to afford substituted isocoumarins. A mechanistic rationale is proposed, implying reductive elimination of Ni(0) promoted by ZnCl(2) cocatalyst as the key step of the catalytic cycle.