A highly efficient, selective synthesis of benzyl esters by palladium catalysis is developed through the bidentate directing group assisted functionalization of multiple C(sp3)–H bonds.
A general palladium catalyzed acetoxylation of benzylicC–H bonds has been developed. Picolinamides serve as an excellent directinggroup for the C–H activation of benzylic methyls. A wide range of 2-amino benzyl alcohol analogues were synthesized in good yields. The products demonstrated broad synthetic utilities toward various benzo-fused heterocycles. Mechanistic studies revealed the key rate-limiting
Selective catalytic synthesis of α-alkylated ketones and β-alkylated secondary alcohols <i>via</i> hydrogen-borrowing
作者:Md. Bakibillah、Sahin Reja、Kaushik Sarkar、Deboshmita Mukherjee、Rajesh Kumar Das
DOI:10.1039/d3nj02295a
日期:——
were shown to be efficient catalysts for α-alkylation of ketones and β-alkylation of secondary alcohols with primary alcohols in the presence of a catalytic amount of the Cp*Ir(III) catalyst and tBuOK in toluene at 110 °C via hydrogen-borrowing and produced substituted ketone products in good to excellent yields. This new C–C bond-formingreaction needs very small amounts of catalyst and base and produces
制备了由吡啶甲酰胺基部分支持的一组三种Ir-( III )配合物。这些络合物被证明是酮的 α-烷基化和仲醇与伯醇的 β-烷基化的有效催化剂,在催化量的 Cp*Ir( III ) 催化剂和t BuOK 的存在下,在甲苯中于 110 °C下通过借氢并以良好至优异的产率生产取代酮产品。这种新的 C-C 键形成反应需要非常少量的催化剂和碱,并且仅产生 H 2 O 作为副产物,使其成为一种有吸引力且环保的方案,可实现酮衍生物的“绿色”合成。
Mechanistic snapshots of rhodium-catalyzed acylnitrene transfer reactions
Rhodium acylnitrene complexes are widely implicated in catalytic C–H amidation reactions but have eluded isolation and structuralcharacterization. To overcome this challenge, we designed a chromophoric octahedral rhodium complex with a bidentate dioxazolone ligand, in which photoinduced metal-to-ligand charge transfer initiates catalytic C–H amidation. X-ray photocrystallographic analysis of the Rh-dioxazolone
铑酰基氮烯配合物广泛参与催化 C-H 酰胺化反应,但一直未能进行分离和结构表征。为了克服这一挑战,我们设计了一种带有二齿二恶唑酮配体的发色八面体铑配合物,其中光诱导的金属到配体的电荷转移引发催化C-H酰胺化。Rh-二恶唑酮复合物的 X 射线光晶体分析可以阐明目标 Rh-酰基氮烯类化合物的结构,并提供确凿的证据证明单线态氮烯类化合物主要负责酰基氨基转移反应。我们还监测到在水晶中亲核试剂与原位生成的 Rh-酰基氮烯类化合物的反应,提供了晶体学可追踪的反应系统来捕获氮烯类化合物转移的机械快照。