Haitao Yang

Bio: Haitao Yang is an academic researcher from Anhui Normal University. The author has contributed to research in topics: Chemistry & Ketone. The author has co-authored 2 publications.

Access to the C2 C–H olefination, alkylation and deuteration of indoles by rhodium(III) catalysis: an opportunity for diverse syntheses

Abstract: A concise approach for the synthesis of structurally diverse indoles enabled by RhIII-catalyzed switchable C2 C–H olefination and alkylation of N-quinolinyl indoles with alkenes as well as highly efficient C–H deuteration is described. The reaction can be conducted under practical reaction conditions, with a broad substrate scope and good tolerance of various functional groups. The potential value of this synthetic methodology is shown by the diverse late-stage modification of the products, thereby providing a straightforward route to access functionalized indoles, especially indole-based P,N ligands.

K2S2O8-mediated acylarylation of unactivated alkenes via acyl radical addition/C–H annulation cascade of N-allyl-indoles with silver cocatalysis

Abstract: A silver-catalyzed, K2S2O8-mediated protocol to access regioselective acylarylation of unactivated alkenes was developed. The reaction between N-allyl-indoles and α-oxocarboxylic acids proceeded smoothly and involved an acyl radical addition/C–H cyclization cascade. The protocol showed a broad substrate scope and good tolerance of functional groups. The reaction proceeded with both internal and terminal alkenes to furnish many functional pyrrolo[1,2-a]indoles bearing the ketone carbonyl group, and this feature also provides the potential to construct structurally complex N-containing heterocycles.

Recent Developments for the Deuterium and Tritium Labeling of Organic Molecules.

Abstract: Organic compounds labeled with hydrogen isotopes play a crucial role in numerous areas, from materials science to medicinal chemistry. Indeed, while the replacement of hydrogen by deuterium gives rise to improved absorption, distribution, metabolism, and excretion (ADME) properties in drugs and enables the preparation of internal standards for analytical mass spectrometry, the use of tritium-labeled compounds is a key technique all along drug discovery and development in the pharmaceutical industry. For these reasons, the interest in new methodologies for the isotopic enrichment of organic molecules and the extent of their applications are equally rising. In this regard, this Review intends to comprehensively discuss the new developments in this area over the last years (2017-2021). Notably, besides the fundamental hydrogen isotope exchange (HIE) reactions and the use of isotopically labeled analogues of common organic reagents, a plethora of reductive and dehalogenative deuteration techniques and other transformations with isotope incorporation are emerging and are now part of the labeling toolkit.

Transition-metal-catalyzed C-H bond alkylation using olefins: recent advances and mechanistic aspects.

Abstract: Transition metal catalysis has contributed immensely to C-C bond formation reactions over the last few decades, and alkylation is no exception. The superiority of such methodologies over traditional alkylation is evident from minimal reaction steps, shorter reaction times, and atom economy while also allowing control over regio- and stereo-selectivity. In particular, hydrocarbonation of alkenes has grabbed increased attention due its fundamental ability to effectively and selectively synthesise a wide range of industrially and pharmaceutically relevant moieties. This review attempts to provide a scientific viewpoint and a systematic analysis of the recent developments in transition-metal-catalyzed alkylation of various C-H bonds using simple and activated olefins. The key features and mechanistic studies involved in these transformations are described briefly.

Transition‐Metal‐Catalyzed, Chelation‐Assisted C‐H Alkenylation and Allylation of Organic Molecules with Unactivated Alkenes

Abstract: Olefins are important building blocks and are widely utilized in synthetic organic chemistry. Owing to its omnipresence and unique reactivity, the functionalization of alkenes has become a powerful method for constructing complex organic molecules. In this context, direct chelation-assisted C−H olefination at the inert C−H bonds represents the most straightforward synthetic method for introducing the alkenyl group into organic compounds in a highly regio- and stereoselective manner. Despite the remarkable advances in chelation-assisted C−H olefination reaction, most of the successful transformations are restricted to activated or electronically biased olefins such as acrylates, styrenes, acrylamides, vinyl sulfones, and vinyl phosphonates. Literature reports on chelation-assisted C−H olefination with unactivated or electronically unbiased alkenes are limited due to poor intrinsic reactivity and regioselectivity issues. Despite significant challenges, the past few years have witnessed tremendous growth. The present review describes the recent advances in the chelation-assisted C−H olefination and allylation of aromatics, alkenes, and heteroaromatics with unactivated alkenes via the concerted-metallation- deprotonation pathway.Transition metals such as palladium, rhodium, iridium and cobalt are widely used for these kind of transformations. The scope, mechanistic investigation, and limitation of the alkenylation and allylation reactions are discussed elaborately. The present review includes all the reported C−H olefination and allylation reactions with unactivated olefins via the base-assisted deprotonation pathway.

Visible-light-induced acylation/cyclization of active alkenes: facile access to acylated isoquinolinones.

Abstract: Nitrogen heterocycles, especially polycyclic compounds, are significant skeletons in valuable molecules. Herein, we developed an efficient and practical visible-light-induced acylation/cyclization of active alkenes with acyl oxime derivatives for constructing acylated indolo/benzimidazo-[2,1,a]isoquinolin-6(5H) ones. This reaction was compatible with various functional groups and a series of fused indole/imidazole skeletons were prepared in up to 95% yield at room temperature.

Metal-free polychloromethyl radical-initiated cyclization of unactivated N-allylindoles towards pyrrolo[1,2-a]indoles.

Abstract: A metal-free polychloromethyl radical-initiated cyclization of unactivated alkenes was developed using CH2Cl2 and CHCl3 as the di- and trichloromethyl radical sources. Variously substituted N-allyl-indoles were successfully transformed into the corresponding C2-(di- and trichloromethyl) pyrrolo[1,2-a]indoles in moderate to good yields. This reaction has a broad substrate scope and good functional group tolerance. Dibromomethylated products can also be obtained using CH2Br2 under standard conditions.