Selenium-Directed Ortho C–H Activation of Benzyl Selenide by a Selenated NHC–Half-Pincer Ruthenium(II) Complex

Abstract

In this work, we report a selenium-directed orthovinylation of benzyl selenide using a Ru(II) catalyst. This novel reaction methodology utilizes selenium as a directing group for C− H activation and tolerates a range of substitutions on both benzyl selenide and different types of vinyls. Incorporation of the directing group is significantly easy and one-pot, and it is a commonly known laboratory reagent. Through this, an effective synthetic methodology has been established for the synthesis of organoselenium while using selenium as a directing group. Moreover, to the best of our knowledge, this is the first report on benzyl selenide functionalization.

Selenated NHC-Pd(II) Pincer Complex Catalyzed, Temperature-Dependent Selective Hydroamination and Oxidative Amination of Olefins: Formation of Enamine Esters and β-Amino Esters under Solvent-Free and Aerobic Conditions

“…Aniline reacts with styrene, para-methoxystyrene, and naphthylstyrene (Scheme 3, 32−34) under standard conditions and produced the desired products in 60%, 62%, and 66% yields, respectively. A nitro-substituted styrene (35) was coupled with aniline to form a 55% yield of desired product. However, the present approach was not found suitable for substituted anilines.…”

“…Although Pd-based catalysts are widely used in a variety of catalytic reactions, some of their critical limitations are low stability and the requirement for an inert atmosphere and a moisture-free environment. , The stability issue can be addressed by selecting the appropriate ligands to maintain the catalytic efficiency of the complex. After the first report of Shaw and Noltes, , pincer ligands have received high attention in the last five decades in the design of various Pd-pincer complexes. − Recently, a new approach to use the chalcogens as one of the donor sites − attracted much attention; the chalcogen (a soft donor) significantly improves the complex’s stability under ambient conditions. The N-heterocyclic carbene (NHC) based chalcogenated pincer ligands show remarkable stability, require low catalyst loading, efficiently work under ambient conditions, and provide a combination of hard and soft donor sites …”

Mechanistic insights and comparative analysis of Ru(ii)–NNC pincer complexes with anionic-, protic-, and classical-NHCs for transfer hydrogenation of ketones

“…[1][2][3][4][5] Their strong σ-donor properties and ease of stereo-electronic modification at nitrogen substituent and carbon backbones of the heterocyclic skeleton have been utilized in the development of complexes with interesting properties and excellent catalytic activities. [6][7][8][9][10][11] A new subclass of NHCs, called protic-NHCs (pNHCs), which bears at least one NH functional group in the N-heterocyclic ring, has become popular in recent years with contributions from Hahn, Ikariya, Kuwata, and several other groups. [12][13][14][15][16][17][18][19][20] The pNHCs have attracted significant attention over the classical NHCs due to the existence of a proton-responsive NH group, allowing H-bonding interactions, β-deprotonations, and nucleophilic additions.…”

Ru-Catalyzed and Selenium-Directed Selective Formation of ortho- and Dialkenylated Selanes, Mixed Organoselenoethers, and Isoselenochromenes

“…8 In 2022, our research group reported an ortho vinylation of benzyl(phenyl)selane employing selenium as a directing group. 7 Functionalizing benzyl(phenyl)selane can benefit organoselenium chemistry by providing new organoseleno compounds, because these are the most significant compounds and serve as efficient skeletons in catalytic reactions and the pharmaceutical industry. 9 Moreover, these compounds have attracted more attention in synthesis, primarily due to their impressive potential use in biological sciences as anticancer, 10 anti-Alzheimer's, 11 antimicrobial, 12 antiviral, 13 anti-inflammatory, 14 antidiabetic 15 agents, etc.…”

“…6 Among the chalcogens, selenium has great potential to act as an efficient directing group without poisoning metal catalysts. 7 In 2020, Tang et al revealed the first instance of Se-directed C−H bond borylation of arene. 8 In 2022, our research group reported an ortho vinylation of benzyl(phenyl)selane employing selenium as a directing group.…”