RESUMO
Correction for 'Visible-light-mediated borylation of aryl and alkyl halides with a palladium complex' by Jia-Hui Zhao, et al., Org. Biomol. Chem., 2020, 18, 4390-4394, DOI: 10.1039/D0OB00028K.
RESUMO
A palladium-catalyzed, photochemical tandem cyclization/dicarbofunctionalization of unactivated alkyl halides containing an alkene moiety offers an appealing route to produce five- or six-membered rings in a redox-neutral fashion. Multisubstituted carbo- and heterocyclic compounds were prepared through the formation of new C-B or C-O bonds, which provides a convenient synthetic route for further transformations. This protocol is characterized by the reaction of alkene regio- and stereoselectivities, good functional group compatibility, wide substrate scope, and mild reaction conditions.
RESUMO
Palladium catalyzed visible-light-mediated borylation of inactivated aryl and alkyl halides is reported; the method provided high yields and excellent functional group compatibility. Furthermore, arylsilicates were synthesized selectively using dimethylphenylsilyl boronic ester via changing the reaction conditions. Finally, the possible reaction mechanism is determined through fluorescence quenching and turn on/off experiments.
RESUMO
The azaborine motif provides a mimic of aromatic systems through replacement of a CâC bond with a B-N bond. In particular, 2,1-borazaronaphthalenes, accessible through robust methods of synthesis and subsequent functionalization, afford an ideal platform to use for a variety of applications. However, the scope of substructures for this archetype has been limited by the lack of nitrogen-containing heteroaryls that can be incorporated within them. In this study, modified reaction conditions were developed to provide access to a wider range of substructures.
Assuntos
Naftalenos/síntese química , Nitrogênio/química , Boratos/química , Estrutura Molecular , Naftalenos/químicaRESUMO
An iodine-promoted one-pot radical cyclization reaction of 1,6-enynes with sulfonyl hydrazides to provide five-membered and hexatomic ring sulfonylated products under the same conditions is established. This reaction proceeded smoothly in water and gave the corresponding products by using I2/TBHP instead of expensive and toxic catalysts with C-S and C-I bond formed in one step. This method also allowed easy access to significant functional sulfones for potential applications in medicinal and organic chemistry.
RESUMO
A silver-promoted oxidative cascade cyclization with a phosphorylation/1,5-aryl migration/desulfonylation/dearomatization process is presented here, providing an efficient method to synthesize azaspiro[4.5]decenones with high regioselectivity. The cinnamamidyl radical, which has rarely been reported before, plays a key role in this reaction.
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A general and metal-free protocol for the construction of benzo[b]fluorenyl thiophosphates was developed through the cascade cyclization of easily prepared diynols and (RO)2P(O)SH, with water as the only byproduct. The novel transformation involved the allenyl thiophosphate as the key intermediate, followed by Schmittel-type cyclization to achieve the desired products. Notably, (RO)2P(O)SH acted not only as a nucleophile but also as an acid-promoter to initiate the reaction.
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A new method for conducting a reductive alkylation/arylation of 1,2-diketones using visible light and unactivated organic halides is presented in this article. This technique does not require a photocatalyst and employs Et3N, a tertiary amine, as a promoter. This amine aids in generating a ketyl radical and an α-aminoalkyl radical, which engages in a C-X bond activation via a halogen atom transfer process (XAT). This approach's success hinges on utilizing Et3N as the promoter. This article's mild and straightforward protocol allows for significantly expanding organic halide substrates, including primary, secondary, and aromatic organic halides and various functional groups.
RESUMO
Described here is a unprecedented organophotoredox/manganese dual catalyzed proton reduction and its application for semi-reduction of alkynes. The catalytic active pre-catalyst [Mn-1] can be feasibly be prepared on gram-scale from Mn(acac)2·2H2O in air. This dual catalytic protocol features noble-metal-free catalysts, simple ligand, and mild conditions. Besides, a unique ortho-halogen and -hydroxyl effect was observed to achieve high Z-stereoselectivity.
RESUMO
Herein, a highly regioselective alkylation of propargylic carbonates for trisubstituted allenes with alkyl 1,4-dihydropyridine derivatives (1,4-DHPs) is developed via a photoredox/nickel dual-catalyzed process, which represents the first direct approach to access alkylated allene products without alkyl organometallic reagents. This method features a broad substrate scope and mild conditions. A hypothetical mechanism with an alkyl radical and an allenyl Ni(III) species is proposed. Benzylation products were also obtained to be the complement building blocks for the potential synthesis of pharmaceuticals.
Assuntos
Alcadienos/síntese química , Carbonatos/química , Níquel/química , Alcadienos/química , Alquilação , Catálise , Estrutura Molecular , Oxirredução , Processos Fotoquímicos , EstereoisomerismoRESUMO
A photocatalytic decarboxylative radical addition bifunctionalization cascade for the synthesis of functionalized alcohols is described. The catalytic cycle is completed through single-electron transfer. The advantages of this reaction are the commercially available materials, wide functional group compatibility, and mild conditions. Notably, some amino acids and bioactive carboxylic acids can provide corresponding products in moderate to good yields, reflecting the potential value in drug development.
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Herein, a highly regioselective propargylic benzylation with propargylic carbonates and benzyl 1,4-dihydropyridine derivatives was developed via a photoredox/palladium dual-catalyzed process, which represents a novel catalytic model for non-terminal propargylic functionalization. The reaction showed excellent regioselectivity and functional group compatibility. A radical coupling mechanism between the propargylic radical and benzyl radical was proposed.
RESUMO
Application of an oxidative amination reagent (di-tert-butyldiaziridinone) to the Ru3(CO)12-catalyzed ortho-selective CAr-H amination reaction is described. This strategy shows good functional group compatibility with various phenyl-substituted N-heterocycles, including biologically active substrates, thus providing synthetic potential for this methodology. Mechanistic studies showed that the reaction process involves an octahedral ruthenium species, and the carbon monoxide ligand plays a crucial role in the C-H activation.
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A novel and highly practical reaction for the copper-catalyzed intermolecular cyanotrifluoromethylation of alkenes is presented here. This methodology provides a general and straightforward way to synthesize a variety of useful CF3-containing nitriles, which can be used for further preparation of pharmaceutically and agrochemically important compounds in synthetic organic chemistry.
Assuntos
Alcenos/química , Cobre/química , Hidrocarbonetos Fluorados/síntese química , Nitrilas/síntese química , Compostos Organometálicos/química , Catálise , Hidrocarbonetos Fluorados/química , Metilação , Estrutura Molecular , Nitrilas/químicaRESUMO
A silver-promoted oxidative cyclization of 1,6-enynes with disubstituted phosphine oxides is developed for the synthesis of fluorene derivatives. The reaction proceeds with high regioselectivity by constructing one C-P bond and two C-C bonds in one step. Moreover, reduction of the pentavalent phosphine enlarges the application scope of the product.
Assuntos
Alcinos/química , Fluorenos/síntese química , Fosfinas/química , Prata/química , Catálise , Ciclização , Fluorenos/química , Estrutura Molecular , Oxirredução , EstereoisomerismoRESUMO
A novel three-component strategy for the cyanotrifluoromethylation/azidotrifluoromethylation and carbocyclization of 1,6-enynes is developed. The reaction proceeds smoothly under a moderate temperature by using a copper catalyst, which provides a rapid and concise access to addition-carbocyclization products. Furthermore, the products obtained can be useful building blocks in discoveries of lead compounds and other biologically active CF3-containing heterocycles.
RESUMO
A new and efficient metal-free cascade cyclization of 1,6-enynes with aldehydes is developed for the synthesis of tricyclic fluorene derivatives. The reaction involves a radical process and one C(sp(2))-C(sp(2)) and two C(sp(2))-C(sp(3)) bonds are formed simultaneously in one pot by using PivOH and TBHP.
Assuntos
Aldeídos/química , Alcenos/química , Alcinos/química , Fluorenos/síntese química , Ciclização , Fluorenos/química , Radicais Livres/químicaRESUMO
Two different cyclic amino esters are synthesized by palladium-catalyzed cross-coupling reaction of diazoesters with N-substituted-2-iodoanilines. Aryldiazoacetates lead to cyclic α-amino esters with an α-quaternary carbon centre in the presence of CO. Additionally, arylvinyldiazoacetates afford cyclic α,ß-unsaturated γ-amino esters.