查看更多>>摘要：Monofluoroalkene is an important motif in drug development as it serves as an ideal mimic of peptide amide bond. Herein, a visible light promoted cross-coupling of ethyl iododifluoroacetate with silyl enol ethers for the synthesis of fl-fluoroenones is presented. The transformation was mediated by non-covalent interactions, in which solvent acts as an electron donor. This protocol can also be applied for the synthesis of a, fl-polyfluoroenones. The advantages of this protocol are mild reaction conditions, excellent functional group tolerance, synthetic flexibility, and operational simplicity. (c) 2022 Elsevier Ltd. All rights reserved.
Tummanapalli, SatyanarayanaBodige, SrinuGulipalli, Kali CharanEndoori, Srinivas...
5页
查看更多>>摘要：Among all biologically active sulfonamides, primary sulfonamides possessing terminal SO2NH2 group occupy special place due to their high zinc binding capability which has been successfully exploited for discovery of several different medicinally active primary sulfonamides. However, majority of the primary sulfonamide synthesis involve traditional method of treating ammonia with sulfonyl chloride, which in turn is typically obtained either from thiols by harsh oxidation conditions or chlorination of sulfonic acids. We herein report a simple and convenient protocol to access primary sulfonamides by direct sulfonylamidation of unfunctionalized arenes [direct C-H activation to C-SO2NH2]. Usefulness of the protocol has been further demonstrated successfully by extending the application to formal syntheses of known drugs, acetazolamide (2), methazolamide (3), ethoxzolamide (4), and a pharmacologically active benzolamide (6). (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：An efficient C3-aminomethylation of imidazo[1,2-a]pyridines with 1,3,5-triazinanes was developed. The eminent advantage of this work is catalyst-free and additive-free. The power of this transformation has been demonstrated by the broad substrate scope and good functional group tolerance. (c) 2022 Elsevier Ltd. All rights reserved.
Reddy, E. PravardhanPadmaja, P.Shekar, P. ChandraReddy, K. Kamalaker...
3页
查看更多>>摘要：An efficient synthesis of 2-aryl-4-chloro-tetrahydropyrans has been accomplished from benzyl chlorides and homoallylic alcohols using FeCl3 as a promoter through a sequential oxidation/Prins cyclization in high yields. This is the first report on the use of benzyl chlorides as surrogates for aldehydes in the Prins cyclization. (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：The iridium-catalyzed oxidative coupling and cyclization of NH isoquinolones with olefins has been realized. Most isoindolo[2,1-b]isoquinolin-5(7H)-one derivatives were obtained in moderate to good yields. Several derivatization reactions including functional group conversion and further C-H/olefin coupling were also performed. This transformation realized the less developed Cp*Ir(III) catalyzed coupling and cyclization reaction of NH substrates with olefins. (c) 2022 Elsevier Ltd. All rights reserved.
Warghude, Prakash K.Bhowmick, AninditaBhat, Ramakrishna G.
7页
查看更多>>摘要：A highly regio- and diastereo-selective [3 + 2] annulation of Morita-Baylis-Hillman carbonates of isatins/ pyrazolones with pyrazolone derived ketimines has been developed to access spiroheterocycles. The protocol worked effectively to construct spirooxindole dihydropyrrole fused pyrazolone and bis-spiropyrazolone dihydropyrrole derivatives bearing two vicinal quaternary spirocentres in good to excellent yields with very high diastereoselectivities under mild catalytic condition at room temperature. The protocol proved to be efficient with diverse MBH carbonates and ketimine derivatives. The method has successfully demonstrated the utility of DMAP as the commercially viable catalyst for this transformation. (c) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：A palladium-catalyzed stereo-selective cis-1,2-arylalkynylation of bicyclic alkenes with aryl triflates and terminal alkynes was developed. This reaction showed high functional group tolerance and can be applied to the modification of bioactive molecules. This three-component reaction provided a practical method for preparing the value-added bicyclo[2.2.1]heptanes derivatives. (c) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：Weakly coordinating functional groups such as keto and ester of common feedstock chemicals have been used efficiently as directing groups for sustainable manganese-catalyzed C-H bond functionalization reactions. This approach is successfully applied in developing C-H addition to oxiranes, imines, olefins, allylic electrophiles, azides, aldehydes and isocyanates via C-C and C-N bonds formation. In some cases reaction cascades resulting in annulated products have also been observed. In this perspective we summarizes on the current developments in organometallic manganese-catalyzed C-H functionalizations driven via weak coordination and have pointed out challenges/opportunities for future catalytic improvements. The mechanistic studies done so far on this emerging topic of manganese catalysis have revealed low valent (0 and +1) manganese complexes more efficient for these transformations. (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：Three new diterpenoids (1-3), along with four known related compounds (4-7), were isolated from the South China Sea soft coral Sinularia pedunculata. Their structures were established by extensive spectroscopic analysis and by comparison of the spectral data with those reported in the literature. The relative configuration of the new compounds was established by spectroscopic analyses and quantum mechanical (QM)-NMR methods. (c) 2022 Elsevier Ltd. All rights reserved.
Shreiber, Scott T.Puchall, Gabriella I.Vicic, David A.
4页
查看更多>>摘要：The homoleptic trifluoromethyl nickel complex [Ni(CF3)4]2- catalyzes a stereoselective trifluoromethylation of brucine with Umemoto II reagent. The trifluoromethylation process proceeds with concomitant isomerization of its alkenyl double bond leading to a trifluoromethylated neobrucine-like derivative. A minor difunctionalization product was also detected from the reaction mixture, consistent with a radical addition process that is occurring in parallel. Stoichiometric reactions between the nickel(II) catalyst precursor and brucine led to no reaction. However, a stochiometric reaction with a high-valent nickel(IV) complex formed trifluoromethylated neobrucine, implicating its intermediacy. (c) 2022 Elsevier Ltd. All rights reserved.
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