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A bithiophene‐alkyne‐based compound was synthesized and first utilized as a palladium ligand for the selective hydrosilylation of allenes with primary and secondary phenylsilanes. It exhibits high selectivity towards a broad range of allenes to produce a single branched allylsilane. It is worth mentioning that the catalytic loading of the palladium as low as 500 ppm can be achieved. This work opens a new front of using bidentate thiophene ligand as a reaction promoter in transition‐metal‐catalyzed organic reaction.
A versatile protocol for the diazenylation of enol silyl ethers under visible light irradiation is presented herein. The reaction is based on the underused reaction of a nitrogen‐based radical (the diazenyl radical) with an enol silyl ether. Arylazo sulfones were used as photoactivatable precursors of these diazenyl radicals. The resulting azaderivatives are potentially bioactive compounds as well as starting materials for the synthesis of N‐containing heterocycles.
Herein, synthesis of benzothiazoles via decarboxylative cross‐coupling between α‐keto acids and 2‐aminothiophenols under blue LED irradiation without using any photocatalyst or metal at room temperature is described. The formation of benzothiazole is driven by EDA complex formed between α‐keto acid and 2‐aminothiophenol. This methodology gives easy access to 2‐substituted and ‐unsubstituted benzothiazoles in moderate to good yields. α‐Keto acids and 2‐aminothiophenols bearing different functional groups were easily transformed in the given conditions.
An imidazolium catalyst supported on thermomorphic polyethylene (PE) was prepared from 1‐methylimidazole and polyethylene iodide (PE‐I). The catalyst was characterized by 1H and 13C NMR, SEC and MALDI‐ToF mass spectrometry. Its catalytic activity was evaluated in the ring‐opening of epoxides with carbon dioxide to give cyclic carbonates under solvent‐free conditions. The catalyst proved to be active at low catalyst loading (down to 0.1 mol%) and allows the reaction to occur at low CO2 pressure (1‐5 bar) and moderate temperature (100°C). A range of terminal and internal epoxides was converted to the corresponding cyclic carbonates with high yields and selectivities. The recyclability of the catalyst was studied and no significant loss of act.
Herein, an electrochemical oxidative cross‐coupling reaction between terminal alkynes and sulfonylhydrazides has been developed. Tetrabutylammonium iodide as the electrolyte and a redox medium.The significant advantages of this method are high atom efficiency, functional group tolerance, and transition metal‐ and oxidant‐free conditions. Most of the compounds exhibit good inhibitory activity on tumor cell lines, and compound 3ag can inhibit cell migration and induce apoptosis in HeLa cells.
A novel highly efficient, environmentally benign Lewis acid‐catalyzed, and protection‐free protocol for the construction of valuable polycyclic products bearing a 1H‐pyrrolo[1,2‐a]indole scaffold is described, starting from readily available propargylic alcohols and 2‐ethynylanilines.
1H‐Pyrroles can be directly functionalized by means of the incorporation of carbene groups from diazocompounds, in a process catalyzed by TpxCu complexes (Tpx = hydrotrispyrazolylborate ligand). The reactions take place with a complete selectivity toward the formal insertion of the carbene into the Cα‐H bond, leading to alkylated pyrroles, with no modification of the Cβ‐H, N‐H or C=C bonds of the pyrrole unit. Alkyl substituents at C‐ring as well as alkyl, aryl, allyl or alkyne substitution at Natom are tolerated, the strategy affording 20 new pyrrole derivatives. The observance of partial deuteration at the methylene group when the reaction is carried out with added D2O serves to discard the direct insertion of the carbene group into the C.
A palladium‐catalyzed intramolecular α‐arylation and defluorinative aromatization strategy for the synthesis of polysubstituted 2‐naphthols is reported. With ortho‐bromobenzyl substituted α‐fluoroketones as the substrates and palladium acetate/triphenylphosphine as the catalyst, this method features good functional group tolerance, readily available catalyst and starting materials, and high yields. The applications of the strategy are demonstrated by the synthesis of useful building blocks, such as naphtha[2,3‐b]furan, naphthol AS‐D, and ligands/catalysts.
Radical reactions have been widely applied in C−P bond‐forming strategies. Most of these strategies require initiators, transition metal catalysts, or organometallic reagents. Herein, a transition metal‐free C(sp3)−P bond formation to prepare α‐aminophosphine oxides via deprotonative radical coupling processes of 2‐azaallyls with chlorodiphenylphosphine oxides was presented. Deprotonation of N‐benzyl imines may generate super‐electron‐donor (SED) 2‐azaallyl anions that reduced chlorodiphenylphosphine oxides to phosphine oxide radicals. Single‐electron transfer (SET) process transformed the 2‐azaallyl anions into 2‐azaallyl radicals, which may couple with phosphine oxide radicals to construct C−P bonds. The deprotonative radical coupling app.
A bithiophene‐alkyne‐based compound was synthesized and first utilized as a palladium ligand for the selective hydrosilylation of allenes with primary and secondary phenylsilanes. It exhibits high selectivity towards a broad range of allenes to produce a single branched allylsilane. It is worth mentioning that the catalytic loading of the palladium as low as 500 ppm can be achieved. This work opens a new front of using bidentate thiophene ligand as a reaction promoter in transition‐metal‐catalyzed organic reaction.
Abstract. Enantioenriched fluorinated monoterpenic alkaloid analogues were synthesised, employing a strategy based on the previously undescribed diastereoselective propargylation of fluorinated tert‐butanesulfinyl imines, and subsequent Pauson‐Khand reaction of resulting enyne derivatives, carried out both stoichiometrically and catalytically.
Abstract. An organocatalyst‐controlled site‐selectivity switchable enantioselective Friedel‐Crafts reaction of unprotected 1‐naphthols has been established for the first time via the conjugate addition of 1‐azadienes. By two chiral complementary squaramide and phosphoric acid, both ortho‐ and para‐selective Friedel‐Crafts alkylations of 1‐naphthols were independently achieved with high efficiency and enantioselectivity. With this strategy, a wide range of optically active triarylmethanes have been achieved in high yields with good to excellent enantioselectivities.
Herein we present the first synthesis of bicyclo[1.1.1]pentyl (BCP) sulfoximines from the corresponding sulfides. Both, BCPs and sulfoximines are bioisosteres used in medicinal chemistry and therefore desirable motifs. The access to BCP sulfides was enabled by the thiol addition to [1.1.1]propellane as published before. A broad scope with specific limitations was discovered for the sulfoximination. To diversify the sulfoximines, N‐acylations and N‐arylations were performed. As the N‐arylation was low yielding we optimized the copper(I) catalyzed reaction. A wide range of aryl iodides could be deployed and competitive reactions showed that aryl bromides react equally fast. In a scale‐up we prepared a suitable precursor for a BCP drug analogu.
Divergent reaction pathways of β‐chlorovinyl ketones have been established to provide the stereodefined alkylidenecyclopent‐2‐enones and 2‐alkenyl furan derivatives. The switch of the reaction pathways was made possible by the microwave‐assisted thermal Nazarov cyclization reaction of β‐chlorovinyl ketones, whereas the soft α‐vinyl enolization of β‐chlorovinyl ketones allowed the generation of allenyl ketone intermediates that in turn smoothly underwent cycloisomerization to the 2‐alkenyl furan derivatives in good to excellent yields.
An iodine mediated base‐controlled reaction between 2‑(pyridin‐2‐yl)acetate derivatives and acrylic esters has been developed for the selective synthesis of 1,3‐disubstituted indolizines and 1,2‐disubstituted indolizines. A single‐pot reaction of 2‑(pyridin‐2‐yl)acetate derivatives and acrylic esters in the presence of CsOAc delivers 1,3‐disubstitued indolizines, while KHCO3 promotes the formation of C3‐iodo indolizines, which could be further de‐iodinated in the presence of copper powder, affording 1,2‐disubstituted indolizines via a sequential stepwise fashion. A plausible reaction mechanism involving radical process has been proposed for this reaction. Pd‐catalzyed reaction of C3‐iodo indolizines with aryl boronic acids has been describe.
Sufonyl indoles are widely recognized as alkylideneindolenine precursors amenable to provide functionalized indole derivatives upon reaction with nucleophiles. In this paper reaction of sulfonyl indoles with indolylmagnesium bromides is used to access unsymmetrical bisindolylmethanes. The target compounds are obtained in satisfactory yields starting from a wide range of substrate/reagent combinations. The utilization of pyrrolylmagnesium bromides for the same reaction also affords the expected adducts albeit in moderate yield.
Herein, we report our study of tertiary radicals, generated through visible light decarboxylation, alkylating 2‐cyanoarenes through radical cross‐coupling at the ipso‐ or the para‐ positions of the cyano groups. Synthesis of a variety of α‐tertiary amines containing quaternary centers is described. The approach enables regio‐selective sequential double alkylation on either 2‐cyanopyridine or 2‐cyanopyrimidine with high efficiency. Our report illustrates the synthetic utility of α‐heteroatom substituted tertiary radicals in synthesis of substituted heteroarenes.
Manganese catalyzed reactions are getting great attention recently due to its high relative abundance and cheap and eco‐friendly behaviour. Application of manganese catalysis in cross‐dehydrogenative coupling is a hottest area since 90% of the contributions are very recent. Dehydrogenation of alcohols using Mn‐pincer system is highly explored nowadays for cross‐coupling to synthesise a variety of products and Mn‐catalyzed C‐H activation, and radical reactions are applied in dehydrogenative coupling of various synthons. This review focuses on the synthesis of synthetically as well as biologically important motifs such as carbonyl compounds, olefins, nitrogen heterocycles, amines, imines etc. using manganese catalyzed dehydrogenative cross co.
In this work, we describe the use of Boron Dipyrromethene (BODIPY) as electron‐withdrawing group for activation of double bonds in asymmetric copper‐catalyzed [3+2] cycloaddition reactions with azomethine ylides. The reactions take place under smooth conditions and with high enantiomeric excess for a large number of different substituents, pointing out the high activation of the alkene by using a boron dipyrromethene as electron‐withdrawing group. Experimental, theoretical studies and comparison with other common electron‐withdrawing groups in asymmetric copper‐catalyzed [3+2] cycloadditions show the reasons of the different reactivity of the boron dipyrromethene derivatives, which can be exploited as a useful activating group in asymmetric.

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