Search

The use of gem‐difluorinated cyclopropanes (gem‐DFCPs) as fluoroallyl surrogates under transition‐metal catalysis has drawn considerable attention recently but such reactions are restricted to producing achiral or racemic mono‐fluoroalkenes. Herein, we report the first enantioselective allylation of indoles under rhodium catalysis with gem‐DFCPs. This reaction shows exceptional branched regioselectivity towards rhodium catalysis with gem‐DFCPs, which provides an efficient route to enantioenriched fluoroallylated indoles with wide substrate scope and good functional group tolerance. [ABSTRACT FROM AUTHOR]

The use of gem‐difluorinated cyclopropanes (gem‐DFCPs) as fluoroallyl surrogates under transition‐metal catalysis has drawn considerable attention recently but such reactions are restricted to producing achiral or racemic mono‐fluoroalkenes. Herein, we report the first enantioselective allylation of indoles under rhodium catalysis with gem‐DFCPs. This reaction shows exceptional branched regioselectivity towards rhodium catalysis with gem‐DFCPs, which provides an efficient route to enantioenriched fluoroallylated indoles with wide substrate scope and good functional group tolerance. [ABSTRACT FROM AUTHOR]

Direct synthesis of gem‐difluorinated carbocyclic molecules represents a longstanding challenge in organic chemistry. Herein, a Rh‐catalyzed [3+2] cycloaddition reaction between readily available gem‐difluorinated cyclopropanes (gem‐DFCPs) and internal olefins has been developed, enabling the efficient synthesis of gem‐difluorinated cyclopentanes with good functional group compatibility, excellent regioselectivity and good diastereoselectivity. The resulting gem‐difluorinated products can undergo downstream transformations to access various mono‐fluorinated cyclopentenes and cyclopentanes. This reaction demonstrates the use of gem‐DFCPs as a type of "CF2" C3 synthon for cycloaddition under transition metal catalysis, which provides potential strategy for synthesizing other gem‐difluorinated carbocyclic molecules. [ABSTRACT FROM AUTHOR]

Direct synthesis of gem‐difluorinated carbocyclic molecules represents a longstanding challenge in organic chemistry. Herein, a Rh‐catalyzed [3+2] cycloaddition reaction between readily available gem‐difluorinated cyclopropanes (gem‐DFCPs) and internal olefins has been developed, enabling the efficient synthesis of gem‐difluorinated cyclopentanes with good functional group compatibility, excellent regioselectivity and good diastereoselectivity. The resulting gem‐difluorinated products can undergo downstream transformations to access various mono‐fluorinated cyclopentenes and cyclopentanes. This reaction demonstrates the use of gem‐DFCPs as a type of "CF2" C3 synthon for cycloaddition under transition metal catalysis, which provides potential strategy for synthesizing other gem‐difluorinated carbocyclic molecules. [ABSTRACT FROM AUTHOR]

As a special class of cyclopropanes, gem -difluorinated cyclopropanes have many fascinating properties as a result of the gem -difluoro substitution; thus, their reactions have received much attention from the synthetic chemistry community. Recently, gem -difluorinated cyclopropanes have gradually emerged as a type of novel and unique fluorinated allylic synthon in cross-coupling reactions for the synthesis of monofluoroalkenes. Herein, we briefly summarize recent advances in transition-metal-catalyzed reactions of gem -difluorinated cyclopropanes. 1 Introduction 2 Palladium-Catalyzed Reactions with Linear Selectivity 3 Palladium-Catalyzed Reactions with Branched Selectivity 4 Other Metal-Catalyzed Reactions 5 Conclusions [ABSTRACT FROM AUTHOR]

Gem -difluorinated cyclopropanes have become an important type of allyl surrogate in transition-metal-catalyzed ring-opening processes, as demonstrated recently through various important advances, especially with palladium catalysis. The versatile fluorinated allyl species generated in this way from gem -difluorinated cyclopropanes exhibit unique advantages compared with conventional allyl sources. By using gem -difluorinated cyclopropanes as allyl surrogates, we achieved a direct allylation of simple arenes through rhodium catalysis under mild conditions. This transformation permits directing-group-free allylation of simple arenes, including electron-neutral, electron-rich, and electron-deficient ones. Here, we give a brief introduction to this area and we discuss our thoughts regarding our recent work and its design. 1 Introduction 2 Our Design 3 Condition Optimization and Substrate Scope 4 Applications in Synthesis 5 Mechanistic Discussions 6 Conclusion and Outlook [ABSTRACT FROM AUTHOR]

Herein, we report a rhodium catalyzed directing‐group free regioselective C−H allylation of simple arenes. Readily available gem‐difluorinated cyclopropanes can be employed as highly reactive allyl surrogates via a sequence of C−C and C−F bond activation, providing allyl arene derivatives in good yields with high regioselectivity under mild conditions. The robust methodology enables facile late‐stage functionalization of complex bioactive molecules. The high efficiency of this reaction is also demonstrated by the high turnover number (TON, up to 1700) of the rhodium catalyst on gram‐scale experiments. Preliminary success on kinetic resolution of this transformation is achieved, providing a promising access to enantio‐enriched gem‐difluorinated cyclopropanes. [ABSTRACT FROM AUTHOR]

Herein, we report a rhodium catalyzed directing‐group free regioselective C−H allylation of simple arenes. Readily available gem‐difluorinated cyclopropanes can be employed as highly reactive allyl surrogates via a sequence of C−C and C−F bond activation, providing allyl arene derivatives in good yields with high regioselectivity under mild conditions. The robust methodology enables facile late‐stage functionalization of complex bioactive molecules. The high efficiency of this reaction is also demonstrated by the high turnover number (TON, up to 1700) of the rhodium catalyst on gram‐scale experiments. Preliminary success on kinetic resolution of this transformation is achieved, providing a promising access to enantio‐enriched gem‐difluorinated cyclopropanes. [ABSTRACT FROM AUTHOR]

Herein, we report a rhodium catalyzed directing‐group free regioselective C−H allylation of simple arenes. Readily available gem‐difluorinated cyclopropanes can be employed as highly reactive allyl surrogates via a sequence of C−C and C−F bond activation, providing allyl arene derivatives in good yields with high regioselectivity under mild conditions. The robust methodology enables facile late‐stage functionalization of complex bioactive molecules. The high efficiency of this reaction is also demonstrated by the high turnover number (TON, up to 1700) of the rhodium catalyst on gram‐scale experiments. Preliminary success on kinetic resolution of this transformation is achieved, providing a promising access to enantio‐enriched gem‐difluorinated cyclopropanes. [ABSTRACT FROM AUTHOR]

The recovery of lanthanides from high level liquid waste (HLLW) is of great significance for both environmental protection and sustainable development of resources. Traditional methods for this purpose are often plagued by poor selectivity, low capacity, and limited acid tolerance. Here we report a new material prepared by impregnating P[5]A-DGA onto porous Amberlite XAD-7 resin for efficient and selective lanthanide adsorption from highly acidic solutions. The as-prepared composite material (PDA resin) shows outstanding sorption efficiency for lanthanides in a wide range of acidities (0.01–3 M HNO 3) and exhibits good selectivity towards lanthanides over different kinds of competing metal ions in simulated nuclear wastewater. Adsorption equilibrium can be achieved within 60 min and the pseudo-second-order model shows better correlation with the kinetic data, indicating that chemical adsorption is the rate determining step. Adsorption isotherm data can be well fitted by Langmuir model, giving a Eu(III) sorption capacity of 33.3 mg/g at 1 M HNO 3 , which is superior to other materials employed for the similar purpose. Importantly, the adsorption capacity can be regenerated by using a mixture of 1 M guanidine carbonate and 0.05 M EDTA-2Na solution as the eluent, and the lanthanide adsorption efficiency from simulated nuclear wastewater remains at the initial level after three desorption-adsorption cycles. Finally, the possible configurations of the ligand-Ln(III) complexes were optimized by DFT calculations, which suggest that each Ln(III) tends to bind to three DGA arms via a nine coordination mode. This research advances the development of pillar[5]arenes for lanthanide recovery by demonstrating a simple and generally applicable method to convert P[5]A-DGA extractant into an efficient adsorbent. [Display omitted] • The first pillar[5]arene-based ligand impregnated resin (PDA) was prepared. • The maximum adsorption capacity for Eu was as high as 33.3 mg/g at 1 M HNO 3. • It can operate in a wide range of acidity (0.01–3 M HNO 3) with good performance. • Simulated nuclear wastewater experiments indicate good selectivity for lanthanides. • PDA resin can be reused for three cycles without decrease in sorption efficiency. [ABSTRACT FROM AUTHOR]