Search

Comprehensive Summary Key Scientists Electron‐rich alkynes, such as ynol and thioynol ethers, have proven to be versatile and appealing partners in catalytic cycloaddition reactions, and thus have raised considerable attentions owing to the practical application in the modular assembly of valuable carbo‐ and heterocycles. The past decades have witnessed inspiring advances in this emerging field, and an increasing number of related discoveries have been exploited. Divided into two main sections on the basis of substrate type, in each section this comprehensive review will initially summarize their synthetic preparations and subsequently examine their reactivity in every sort of catalytic cycloaddition with emphasis on the methodology development, aimed at providing an access to this burgeoning area and encouraging further innovations in the near future. For the cycloaddition of ynol ethers, in 2004, Kozmin et al. firstly developed a silver‐catalyzed [2 + 2] cycloaddition of siloxy alkynes with electron‐poor olefins. In 2012, Hiyama et al. realized a palladium‐catalyzed formal [4 + 2] annulation of alkynyl aryl ethers with internal alkynes. In the same year, Sun et al. discovered an efficient [6 + 2] cyclization between siloxy alkynes and 2‐(oxetan‐3‐yl)benzaldehydes by applying HNTf2 as catalyst. In 2017, Wender et al. first utilized vinylcyclopropanes (VCPs) as coupling partners in the [5 + 2] annulation of ynol ethers. In 2018 and 2020, Ye et al. reported zinc‐catalyzed formal [3 + 2] and [4 + 3] cycloaddition, respectively. For the cycloaddition of thioynol ethers, in 2004, Hilt et al. realized a [4 + 2] cycloaddition by employing the alkynyl sulfides and acyclic 1,3‐dienes. In 2006, a ruthenium‐catalyzed [2 + 2] cycloaddition of thioynol ethers with bicyclic alkenes was accomplished by Tam. In 2014, Sun et al. reported an elegant iridium‐catalyzed click reaction of thioalkynes with azides. [ABSTRACT FROM AUTHOR]

The article explores recent advancements in the asymmetric Doyle-Kirmse reaction, a chemical reaction that produces chiral sulfides. It discusses different strategies and catalysts used to achieve high enantioselectivity in the reaction, as well as the role of chiral metal-bound ylides in controlling the stereoselectivity. The text also highlights the challenges and future directions for further development in this area. Overall, the article provides valuable insights into the current state and potential future advancements in this field of research. [Extracted from the article]

A metal‐ and oxidant‐free procedure for the three‐component haloazidation/cyclization of phenyl‐linked 1,6‐enynes with TMSN3 and N‐iodo(bromo)succinimide under the irradiation of visible light was described. Moreover, this reaction involved a radical addition/5‐exo‐dig cyclization/radical coupling process, and realized simultaneous construction of C−N, C−C, and C−X (I, Br) bonds in one step. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Aryl sulfonyl radical triggered cascade cyclization of phenyl‐linked 1,6‐enynes for the synthesis of biologically important indenes containing alkenyl C—X bonds and 10a,11‐dihydro‐10H‐benzo[b]fluorines is presented. In these radical cascade processes, three new chemical bonds, including C—S, C—C, and C—X bonds, and three C—C bonds are formed in one step. The method is attractive and valuable due to its metal‐free, mild reaction conditions, broad substrate scope and good functional group tolerance. [ABSTRACT FROM AUTHOR]

3-Methyl-6-(3,5-difluorophenyl)imidazo[2,1-b]thiazole (mdfpit) and 3-methyl-6-(3,4,5-trifluorophenyl)imidazo[2,1-b]thiazole (mtfpit) were easily prepared from thiourea, acetone, and 3,5-difluorobenzoyl bromide or 3,4,5-trifluorobenzoyl bromide. These were used as primary ligands to synthesize twelve phosphorescent IrIII complexes with picolinic acid (pic), isoquinoline-3-carboxylic acid (3-IQA), quinoline-2-carboxylic acid (2-QA), 2-(pyridin-2-yl)phenol (2-ylppy), 2-(2,4-difluorophenyl)pyridine (dfppy), and pyridine-2-sulfonic acid (2-sappy) as auxiliary ligands. Their structures, photoluminescence, and electrochemical properties were investigated. Upon introducing more fluorine atoms into the benzene ring of the primary ligand, the thermal stability, photoluminescence quantum yield (PLQY), LUMO energy level, and luminous efficiency of the resulting IrIII complexes are significantly improved, and the photoluminescence emission spectra are blue-shifted. Their maximum emission wavelengths are present in the range of 517–618 nm, and the luminous colors span from the green to red light region. Using the synthesized IrIII complexes as emitters, LED chips based on InGaN chip excitation were developed, which showed good performances. Among all LEDs, the PLQY of the (mtfpmt)2Ir(pic) based LED is 58.4%, and the luminous efficiency is as high as 17.11 lm W−1; the luminous efficiency of the (mdfpmt)2Ir(2-QA) based LED is 3.41 lm W−1 with CIE coordinates of 0.60 and 0.38, which are very similar to the saturated standard red light emission. The results demonstrate the potential of the studied IrIII complexes as candidates for LED materials. [ABSTRACT FROM AUTHOR]

Three iridium complexes of (dfppy)2Ir(DAPB), (dfppy)2Ir(DAPB), and (dfppy)2Ir(DAPB) were synthesized by using phosphine carbonylimide derivative as auxiliary ligand and fluoro−/trifluoromethyl substituted 2‐phenylpyridine derivatives as primary ligands. Their quantum efficiency range from 19.4% to 38.5%, and show strong rigidochromic effect. The maximum emission wavelengths of solid‐state fluorescence have remarkable red shifts from 39 to 55 nm compared with these in CH2Cl2. [ABSTRACT FROM AUTHOR]

In the academic field, no previous work has been done on quantifying the relationship between farmers' scientific literacy and their livelihood capitals. On the basis of field research in county M and correlation analysis, the relationship between farmers' scientific literacy and their livelihood capitals is as follows: farmers' scientific literacy and human capital is moderately correlated, whereas farmers' scientific literacy and natural capital is negatively correlated. Farmers' scientific literacy has a weak positive correlation with physical capital and financial capital, whereas the relationship between farmers' scientific literacy and social capital is hardly evident. A regression analysis further reveals that in county M, human capital and financial capital have the closest relationship with farmers' scientific literacy. [ABSTRACT FROM AUTHOR]

A novel three-component Pd/norbornene cooperative catalysis cascade decarboxylative [2+2+2]/[2+2+3]cyclization of 4-iodoisoquinolin-1(2 H )-ones and o -bromobenzoic acids or 8-bromo-1-naphthoic acid has been developed. The method affords a range of fused phenanthridinones and hepta[1,2- c ]isoquinolinones and displays unique regioselectivity and broad substrate scope. Palladium/norbornene (Pd/NBE)-catalyzed C-H activation and subsequent decarboxylative coupling reactions were involved, and NBE acts as a building block for the construction of rigid nonplanar molecular architectures.