In the last few years, the development of versatile methodologies to incorporate trifluoromethyl groups into organic molecules has attracted significant attention in synthetic chemistry. This review ...gives an overview over the development on the trifluoromethylation of alkynes, which have not been solely discussed before. Formation of diverse C(sp, sp2, sp3)CF3 bonds are all covered in this review.
Versatile methodologies for the incorporation of trifluoromethyl groups into organic molecules have attracted significant attention in synthetic chemistry. This Minireview highlights the recent efforts on the development of trifluoromethylation of alkynes to construct various diverse C(sp, sp2, sp3)CF3 bonds by radical processes, or through transition‐metal catalysis by using nucleophilic or electrophilic trifluoromethylation reagents (see scheme).
A copper-catalyzed intramolecular trifluoromethylation of arylacrylamides leads to oxindole derivatives, effected with stable and inexpensive Langlois' reagent (CF3SO2Na). These reactions proceed via ...a radical process in water at room temperature. The aqueous solution can be recycled.
Elaborated molecular architectures including complex carbocycles, heterocycles, and polycyclic molecular structures represent an important class of organic compounds because they are ubiquitous ...structural units in a broad variety of biologically and pharmacologically relevant natural products, medicinal molecules, and functional materials. A major challenge in modern synthetic methodology is the development of strategically efficient and selective construction of these compounds from readily available starting materials. Transition‐metal‐catalyzed transformations involving Heck reaction as the pivotal step have afforded a powerful approach for accessing sophisticated polycyclic skeletons from a set of easy‐to handle starting materials, thus highlighting its potential significance in streamlining the drug discovery process. Over the past few decades, significant effort has been devoted to accessing complex polycyclic derivatives in efficient and versatile routes, and a number of powerful and direct synthetic strategies have been reported. In this review, the latest advances in transition‐metal‐catalyzed transformations involving Heck reaction as the critical step are summarized, which could be divided into six categories: 1) Heck/Sonogashira tandem reaction; 2) Heck/Suzuki tandem reaction; 3) Heck/Heck tandem reaction; 4) Heck/Hiyama tandem reaction; 5) Heck/Cacchi tandem reaction; 6) Heck/C−H bond functionalization tandem reaction.
Multicomponent reactions are fundamentally different from two-component reactions, as multicomponent reactions can enable the efficient and step-economical construction of complex molecular scaffolds ...from simple precursors. Here, an unprecedented three-component direct C–H addition was achieved in the challenging meta-selective fashion. Fluoroalkyl halides and a wide range of alkenes, including vinylarenes, unactivated alkenes, and internal alkenes, were employed as the coupling partners of arenes in this strategy. The detailed mechanism presented is supported by kinetic isotope studies, radical clock experiments, and density functional theory calculations. Moreover, this strategy provided access to various fluoride-containing bioactive 1,1-diarylalkanes and other challenging synthetically potential products.
Elaborated molecular architectures, especially carbocyclic, heterocyclic, endocyclic, and polycyclic molecular structures, serve as an important class of organic complexes because they are frequently ...occurring core structural units in a variety of biologically and pharmacologically relevant natural products, drug molecules, agrochemicals, and functional materials. A main challenge of current synthetic approaches is the development of strategically efficient and selective formation of these compounds from easy‐to‐handle starting materials. The cascade cyclizations of 1,7‐enynes have afforded an indispensable method for accessing molecular complexity and diversity, thus highlighting their potential significance in both academic and industrial communities. In the last decades, tremendous efforts have been devoted to discovering convenient routes to access sophisticated annulation derivatives, and a wide range of powerful and straightforward synthetic strategies have been reported. In this review, the latest achievements in the cascade cyclization reactions of 1,7‐enynes are summarized, which could be separated into three categories: (1) Visible‐light‐induced reactions of 1,7‐enynes; (2) Metal‐free catalyzed reactions of 1,7‐enynes; (3) Transition‐metal‐catalyzed reactions of 1,7‐enynes.
A copper‐catalyzed difunctionalizing trifluoromethylation of activated alkynes with the cheap reagent sodium trifluoromethanesulfinate (NaSO2CF3 or Langlois’ reagent) has been developed incorporating ...a tandem cyclization/dearomatization process. This strategy affords a straightforward route to synthesis of 3‐(trifluoromethyl)‐spiro4.5trienones, and presents an example of difunctionalization of alkynes for simultaneous formation of two carbon–carbon single bonds and one carbon–oxygen double bond.
Spiro mania: A copper‐catalyzed difunctionalizing trifluoromethylation of activated alkynes with the cheap reagent NaSO2CF3 has been reported, affording a series of 3‐trifluoromethyl spiro4.5trienones through a tandem cyclization/dearomatization process. In this alkyne difunctionalization process, two carbon–carbon bonds and one carbon–oxygen double bond are simultaneously formed.
In recent years, the synthesis of C‐aryl glycosides hrough C−H functionalization has attracted extensive attention of organic synthesis chemists due to its steps and atomic economy. In this concept, ...we systematically summarizes the synthesis of C‐aryl glycosides with diverse regioselectivity and diastereoselectivity from the perspective of C−H arylation of glycosides and C−H glycosylation of arenes. It can be found that a series of recently developed C−H glycosylation reactions have higher site‐selectivity and diastereomeric selectivity than Friedel–Crafts glycosylation reaction. The reaction conditions are milder, which can be compatible with acid‐sensitive protective groups, such as acetals or ketals, and the deprotection is more convenient. It can be seen that there are few reports on remote C−H glycosylation of aromatic hydrocarbons, which is a new field and needs further research. In addition, C−H glycosylation has a lot of shortcomings, which need to be further explored: a) the precise regulation of stereoselectivity in the reaction process also needs further optimization; b) the research on the reaction mechanism is almost limited to DFT calculation, and there is no exact experimental evidence. For key parts, such as the specific reaction mechanism between cyclo‐metal intermediates and glycosyl donors in ortho‐CAr−H glycosylation is still unclear; c) due to the fact that aryl glycoside compounds contain bare hydroxyl groups in practical applications, it is an urgent problem to realize the compatibility of glycoside substrates containing naked hydroxyl groups or to remove the protective groups on hydroxyl groups by a mild and efficient method after the reaction; d) In this rapidly developing field, we need to study a greener, more economical and more practical C−H glycosylation of arenes in the future, which will be conducive to the synthesis of C‐aryl glycosides with more biological application significance.
C‐aryl glycosides synthesis through C−H functionalization does not require pre‐functionalization of the substrate, and has high step economy and atomic economy. Therefore, from the perspective of C−H arylation of glycosides and C−H glycosylation of arenes, this Concept article systematically summarizes the synthesis strategies of C‐aryl glycosides with different positional selectivity.
An acid for a phosphine: A versatile protocol for preparation of various di(phenyl)phosphoryl oxides was developed by copper‐catalyzed decarboxylative coupling of alkenyl, alkynyl carboxylic acids, ...and N‐benzylproline, respectively, with R2P(O)H (see scheme). All classes of products are important precursors for preparation of biologically active molecules and various phosphorus ligands. This finding represents the first example of copper‐catalyzed decarboxylative coupling to construct CP bonds.
The development of a direct vinylogous Michael addition of linear nucleophilic substrates is a long‐standing challenge because of the poor reactivity and the considerable difficulty in controlling ...regioselectivity. By employing a rationally designed multifunctional supramolecular iminium catalysis strategy, the first direct vinylogous Michael addition of unmodified linear substrates to α,β‐unsaturated aldehydes, to afford chiral 1,7‐dioxo compounds with good yields and excellent regio‐ as well as enantioselectivity, has been developed.
Fall into line: The title catalysis strategy was developed for addressing the long‐standing problem of the direct vinylogous Michael addition of unmodified linear dienol substrates. The desired 1,7‐dioxo compounds were obtained with good yields and excellent regio‐ and enantioselectivity. DCE=1,2‐dichloroethane, TMS=trimethylsilyl.
As one of the most widely investigated compound skeleton, quinolines possess important medicinal and biological activities. As such, a great number of literatures, including reviews, have reported ...various methodologies to construct quinolines. Recently, organocatalyzed reactions have attracted the attention of organic chemists due to its being "green" because the reactions avoid the use of toxic metals. In this review, various distinctive contributions are surveyed with specific emphasis on organocatalyzed reactions for quinoline core constructions.
