Enantioselective C−H Activation with Earth‐Abundant 3d Transition Metals

Angewandte Chemie International Edition, Год журнала: 2019, Номер 58(37), С. 12803 - 12818

Опубликована: Май 11, 2019

Molecular syntheses largely rely on time- and labour-intensive prefunctionalization strategies. In contrast, C-H activation represents an increasingly powerful approach that avoids lengthy of prefunctionalized substrates, with great potential for drug discovery, the pharmaceutical industry, material sciences, crop protection, among others. The enantioselective functionalization omnipresent bonds has emerged as a transformative tool step- atom-economical generation chiral molecular complexity. However, this rapidly growing research area remains dominated by noble transition metals, prominently featuring toxic palladium, iridium rhodium catalysts. Indeed, despite significant achievements, use inexpensive sustainable 3d metals in asymmetric activations is still clearly its infancy. Herein, we discuss remarkable recent progress transformations via organometallic base up to April 2019.

Язык: Английский

---

Toolbox for Distal C–H Bond Functionalizations in Organic Molecules

Chemical Reviews, Год журнала: 2021, Номер 122(6), С. 5682 - 5841

Опубликована: Окт. 18, 2021

Transition-metal-catalyzed C–H activation has developed a contemporary approach to the omnipresent area of retrosynthetic disconnection. Scientific researchers have been tempted take help this methodology plan their synthetic discourses. This paradigm shift helped in development industrial units as well, making synthesis natural products and pharmaceutical drugs step-economical. In vast zone bond activation, functionalization proximal bonds gained utmost popularity. Unlike bonds, distal is more strenuous requires distinctly specialized techniques. review, we compiled various methods adopted functionalize mechanistic insights within each these procedures, scope methodology. With give complete overview expeditious progress made field organic chemistry while also highlighting its pitfalls, thus leaving open for further modifications.

Язык: Английский

---

Transition-Metal-Catalyzed, Coordination-Assisted Functionalization of Nonactivated C(sp³)–H Bonds

Chemical Reviews, Год журнала: 2021, Номер 121(24), С. 14957 - 15074

Опубликована: Окт. 29, 2021

Transition-metal-catalyzed, coordination-assisted C(sp3)–H functionalization has revolutionized synthetic planning over the past few decades as use of these directing groups allowed for increased access to many strategic positions in organic molecules. Nonetheless, several challenges remain preeminent, such requirement high temperatures, difficulty removing or converting groups, and, although metals provide some reactivity, employing outside palladium. This review aims give a comprehensive overview coordination-assisted, transition-metal-catalyzed, direct nonactivated bonds by covering literature since 2004 order demonstrate current state-of-the-art methods well limitations. For clarity, this been divided into nine sections transition metal catalyst with subdivisions type bond formation. Synthetic applications and reaction mechanism are discussed where appropriate.

Язык: Английский

---

The Fluorination of C−H Bonds: Developments and Perspectives

Angewandte Chemie International Edition, Год журнала: 2019, Номер 58(42), С. 14824 - 14848

Опубликована: Фев. 13, 2019

Abstract This Review summarizes advances in fluorination by C(sp 2 )−H and 3 activation. Transition‐metal‐catalyzed approaches championed palladium have allowed the installation of a fluorine substituent at ) sites, exploiting reactivity high‐oxidation‐state transition‐metal fluoride complexes combined with use directing groups (some transient) to control site stereoselectivity. The large majority known methods employ electrophilic reagents, but combining nucleophilic source an oxidant appeared. External ligands proven be effective for directed weakly coordinating auxiliaries, thereby enabling over reactivity. Methods relying on formation radical intermediates are complementary transition‐metal‐catalyzed processes as they allow undirected fluorination. To date, C−H fluorinations mainly N−F reagents unique Mn III ‐catalyzed oxidative using has been developed. Overall, field late‐stage progressed much more slowly, state play explaining why 18 F‐fluorination is still its infancy.

Язык: Английский

---

Rhodium‐Catalyzed C(sp²)‐ or C(sp³)−H Bond Functionalization Assisted by Removable Directing Groups

Angewandte Chemie International Edition, Год журнала: 2018, Номер 58(25), С. 8304 - 8329

Опубликована: Окт. 12, 2018

Abstract In recent years, transition‐metal‐catalyzed C−H activation has become a key strategy in the field of organic synthesis. Rhodium complexes are widely used as catalysts variety functionalization reactions because their high reactivity and selectivity. The availability number rhodium various oxidation states enables diverse reaction patterns to be obtained. Regioselectivity, an important issue chemistry, can accomplished by using directing group assist reaction. However, obtain target functionalized compounds, it is also necessary use that easily removed. A wide range directed catalyzed have been reported date. this Review, we discuss Rh‐catalyzed aided removable such phenol, amine, aldehyde, ketones, ester, acid, sulfonic N‐heteroaromatic derivatives.

Язык: Английский

---

Late‐Stage Peptide Diversification by Position‐Selective C−H Activation

Angewandte Chemie International Edition, Год журнала: 2018, Номер 57(45), С. 14700 - 14717

Опубликована: Июль 3, 2018

The late-stage modification of structurally complex peptides bears great potential for drug discovery, crop protection, and the pharmaceutical industry, among others. Whereas traditional approaches largely rely on prefunctionalizations, C-H activation catalysis has in recent years emerged as an increasingly powerful tool post-translational peptide modifications a step-economic manner. Herein, we summarize progress organometallic until June 2018, including position- chemoselective palladium-, ruthenium-, manganese-catalyzed processes.

Язык: Английский

---

Transition Metal‐Catalyzed Enantioselective C−H Functionalization via Chiral Transient Directing Group Strategies

Angewandte Chemie International Edition, Год журнала: 2020, Номер 59(45), С. 19773 - 19786

Опубликована: Июль 20, 2020

Abstract Transition metal‐catalyzed enantioselective functionalization of C−H bond, the most abundant functionality in organic molecules, has emerged as an expedient synthetic approach to streamline synthesis complex chiral molecules. Despite significant progress, traditional directing group‐enabled strategies require additional steps for installation and removal groups from target molecule. The recently developed asymmetric using transient ( c TDGs) offers a promising alternative that can circumvent this obstacle therefore simplify process. In Minireview, we briefly discuss advent recent advances emerging concept, with emphasis on discussing creation various stereogenic centers developments TDGs. Applications natural product ligand derivatizations are also discussed. We hope Minireview will highlight great potential strategy help inspire further endeavors.

Язык: Английский

---

Palladium-Catalyzed C(sp3)–H Bond Functionalization of Aliphatic Amines

Chem, Год журнала: 2019, Номер 5(5), С. 1031 - 1058

Опубликована: Фев. 1, 2019

Язык: Английский

---

Enantioselective Pallada‐Electrocatalyzed C−H Activation by Transient Directing Groups: Expedient Access to Helicenes

Angewandte Chemie International Edition, Год журнала: 2020, Номер 59(32), С. 13451 - 13457

Опубликована: Апрель 3, 2020

Abstract Asymmetric pallada‐electrocatalyzed C−H olefinations were achieved through the synergistic cooperation with transient directing groups. The electrochemical, atroposelective activations realized high position‐, diastereo‐, and enantio‐control under mild reaction conditions to obtain highly enantiomerically‐enriched biaryls fluorinated N−C axially chiral scaffolds. Our strategy provided expedient access to, among others, novel BINOLs, dicarboxylic acids helicenes of value asymmetric catalysis. Mechanistic studies by experiments computation key insights into catalyst's mode action.

Язык: Английский

---

Electroremovable Traceless Hydrazides for Cobalt-Catalyzed Electro-Oxidative C–H/N–H Activation with Internal Alkynes

Journal of the American Chemical Society, Год журнала: 2018, Номер 140(25), С. 7913 - 7921

Опубликована: Май 29, 2018

Electrochemical oxidative C–H/N–H activations have been accomplished with a versatile cobalt catalyst in terms of [4 + 2] annulations internal alkynes. The electro-oxidative C–H activation manifold proved viable an undivided cell setup under exceedingly mild reaction conditions at room temperature using earth-abundant catalysts. electrochemical catalysis prevents the use transition metal oxidants catalysis, generating H2 as sole byproduct. Detailed mechanistic studies provided strong support for facile cobaltation by initially formed cobalt(III) catalyst. subsequent alkyne migratory insertion was interrogated mass spectrometry and DFT calculations, providing formation key seven-membered cobalta(III) cycle regioselective fashion. Key to success unprecedented alkynes represented N-2-pyridylhydrazides, which we developed traceless electrocleavage strategy electroreductive samarium temperature.

Язык: Английский

---