查看更多>>摘要：? 2021The facile synthesis of a highly reactive α-bromocaranone from (+)-carene is reported. This intermediate was found to generate diverse chiral building blocks through radical or carbocation mediated cyclopropyl fragmentation reactions in moderate to excellent yields. Furthermore, the formation of an unexpected carvone derivative prompted several control studies that provided mechanistic insight into an unusual transformation. This study not only demonstrates the synthesis of a variety of chiral building blocks but provides insight into the reactivity of keto-halo-cyclopropanes in general.
查看更多>>摘要：? 2021 Elsevier LtdAn efficient approach to salicylates via a novel transformation of anionically activated aromatic trifluoromethyl group is described. Anionically activated trifluoromethyl group can react with phenols/alcohols under alkaline conditions to afford aryl/alkyl salicylates in high yields. Mechanism studies indicate that the carbonyl oxygen atom of ester is from the H2O in the solvent.
查看更多>>摘要：? 2021 Elsevier LtdElectrochemical oxidation-induced direct carbonylation of benzyl C–H bond for the synthesis of aromatic α-diketones is described. In this process, tetrabutylammonium iodide (nBu4NI) not only acts as an electrolyte, but its iodine anion is oxidized to an iodine radical at the anode, acting as a hydrogen atom transfer agent. The iodine radical extracts the benzyl hydrogen atom and causes the carbonylation of the benzyl position, where O2 in the air is used as an oxygen source.
查看更多>>摘要：? 2021 Elsevier LtdA radical cascade difluoroalkylation-cyclization of β-Caryophyllene with iododifluoromethyl ketones provides a practical method for the synthesis of difluoroalkylated protoilludanes in excellent yield. Further, these fluorinated compounds displayed interesting biological activities against human ovarian cancer cells (A2780 and SKOV-3) and lung cancer cells (A549) showcasing the value of this modification strategy.
查看更多>>摘要：? 2021 Elsevier LtdUsing commercially available and cheap carboxylic acids as alkylating reagents, a practical methodology for the visible-light induced decarboxylative alkylation of quinoxalin-2(1H)-ones was developed. The reaction proceeds in the absence of metal-catalyst, acid or basic additive, or external photosensitizer, making it an environmentally friendly and attractive protocol for the alkylation of quinoxalines.
查看更多>>摘要：? 2021 Elsevier LtdAn Efficient Pd@Pro-GO heterogeneous catalyst was developed that can promote the α, β-dehydrogenation of saturated aldehyde and ketones in the yield of 73% ? 92% at mild conditions without extra oxidants and additives. Pd@Pro-GO heterogeneous catalyst was synthesized via two steps: firstly, the Pro-GO was obtained by the esterification reaction between graphene oxide (GO) and N-(tert-Butoxycarbonyl)-L-proline (Boc-Pro-OH), followed by removing the protection group tert-Butoxycarbonyl (Boc), which endowed the proline-functionalized GO with both the lewis acid site (COOH) and the bronsted base site (NH), besides, the pyrrolidine of proline also can form imine with aldehydes to activate these substrates; Second, palladium was dispersed on the proline-functionalized GO (Pro-GO) to obtained heterogeneous catalyst Pd@Pro-GO. Mechanistic studies have shown that the Pd@Pro-GO-catalyzed α,β-dehydrogenation of saturated aldehyde and ketones was realized by an improved heterogeneously catalyzed Saegusa oxidation reaction. Based on the obove characteristics, the Pd@Pro-GO will be widely used in the transition metal catalytic field.
查看更多>>摘要：? 2021 Elsevier LtdIn this paper, we reported a copper-catalyzed ring-opening reaction of arylcyclopropanes by N-fluorobenzenesulfonimide, leading to N-allylsulfonamides in moderate to good yields. This procedure tolerated bromo, fluoro, trifluoromethyl, phenyl and alkyl groups in the phenyl, proceeding with a sequential ring-opening of arylcyclopropanes, and copper-mediated β-H elimination of alkyl radical.
查看更多>>摘要：? 2021 Elsevier Ltd1H-Pyrrol-2(5H)-ones synthesized via a modified literature procedure from primary amines, 3-substituted propiolic acids, isocyanides and glyoxal underwent a facile Regitz diazo transfer to give novel heterocyclic α-diazocarbonyl compounds – polysubstituted diazo pyrrol-2-ones.
查看更多>>摘要：? 2021 Elsevier LtdA method for isoindoline synthesis via phosphazene base-catalyzed intramolecular hydroamination of aminoalkenes was developed. The reaction has a broad functional group tolerance, including for halide, cyano, and methoxy groups, and could also be used to synthesize tetrahydroisoquinoline, pyrrolidine, and piperidine. The method was used as a key step in the total synthesis of aristocularine in six steps in 35% overall yield. The strategy involved the construction of an isoindoline core through controlling the formation of the desired C–N bond, with the relatively labile methoxymethyl group and arylbromide remaining intact.
查看更多>>摘要：? 2021 Elsevier LtdA palladium-catalyzed synthesis of indole fused α-carbolines (pyridodiindoles) from 2,3′-biindoles and nitriles has been developed. This conversion involves the double C–H activation and cyclization of 2,3′-biindoles with nitriles via C–C and C–N bond formation in a single step. However, C-3 cyanated biindoles were formed through a retro-Mannich pathway when the reaction was carried out with ethyl cyanoacetate.
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