With the assistance of a practical directing group (COAQ), the first catalytic protocol for the palladium-catalyzed C(sp3)–H monoarylation of methanol has been developed, offering an invaluable synthesis means to establish extensive derivatives of crucial arylmethanol functional fragments. Furthermore, the gram-scale reaction, broad substrate scope, excellent functional group compatibility, and even
Herein, we report the development of a tailored cobalt catalyst system of Cp*Co(III)(LX) toward intramolecular C-H nitrene insertion of azidoformates to afford cyclic carbamates. The cobalt complexes were easy to prepare and bench-stable, thus offering a convenient reaction protocol. The catalytic reactivity was significantly improved by the electronic tuning of the bidentate LX ligands, and the observed
enantioselective C(sp3)-H functionalization reactions are still highly desirable. In particular, the ability to use attractive noncovalent interactions for rate acceleration and enantiocontrol would significantly expand the current arsenal for asymmetric metal catalysis. Herein, we report the development of a highly enantioselective Ir(III)-catalyzed intramolecular C(sp3)-H amidation reaction of dioxazolone
尽管在过去十年中取得了显着进展,但在对映选择性 C(sp3)-H 官能化反应中手性催化剂的新设计策略仍然是非常需要的。特别是,使用有吸引力的非共价相互作用进行速率加速和对映控制的能力将显着扩展不对称金属催化的当前武器库。在此,我们报告了高对映选择性 Ir(III) 催化的二恶唑酮底物的分子内 C(sp3)-H 酰胺化反应的开发,该反应用于使用新设计的基于 α-氨基酸的手性配体合成光学富集的 γ-内酰胺。这种 Ir 催化的反应在非常温和的条件下以优异的效率进行,并对活化和未活化的烷基 C(sp3)-H 键具有出色的对映选择性。它为γ-烷基γ-内酰胺的不对称合成提供了第一条通用路线。发现水是一种独特的共溶剂,可在 γ-芳基内酰胺生产中实现出色的对映选择性。机理研究表明,配体在 Ir 中心周围形成了一个明确的凹槽型手性袋。该口袋的疏水作用允许在极性或水性介质中轻松立体控制底物结合。这种新的 Ir
Divergence between Organometallic and Single-Electron-Transfer Mechanisms in Copper(II)-Mediated Aerobic C–H Oxidation
作者:Alison M. Suess、Mehmed Z. Ertem、Christopher J. Cramer、Shannon S. Stahl
DOI:10.1021/ja4026424
日期:2013.7.3
Copper(II)-mediated C-H oxidation is the subject of extensive interest in synthetic chemistry, but the mechanisms of many of these reactions are poorly understood. Here, we observe different products from Cu(II)-mediated oxidation of N-(8-quinolinyl)benzamide, depending on the reaction conditions. Under basic conditions, the benzamide group undergoes directed C-H methoxylation or chlorination. Under
铜 (II) 介导的 CH 氧化是合成化学中广泛关注的主题,但对其中许多反应的机制知之甚少。在这里,我们观察到来自铜(II)介导的 N-(8-喹啉基)苯甲酰胺氧化的不同产物,具体取决于反应条件。在碱性条件下,苯甲酰胺基团发生定向的 CH 甲氧基化或氯化。在酸性条件下,喹啉基团发生非定向氯化。实验和计算机制研究表明,前一种条件下的有机金属 CH 活化/功能化机制和后一种条件下的单电子转移机制。这种罕见的发散性观察,
Urethans as Local Anesthetics. III. Alkyl N-(8-Quinolyl) Carbamates