Carboazidation of alkenes and alkynes holds the promise to construct valuable molecules directly from chemical feedstock therefore is significantly important. Although a few examples have been ...developed, there are still some unsolved problems and lack of universal methods for carboazidation of both alkenes and alkynes. Here we describe an iron-catalyzed rapid carboazidation of alkenes and alkynes, enabled by the oxidative radical relay precursor t-butyl perbenzoate. This strategy enjoys success with a broad scope of alkenes under mild conditions, and it can also work with aryl alkynes which are challenging substrates for carboazidation. A large number of diverse structures, including many kinds of amino acid precursors, fluoroalkylated vinyl azides, other specific organoazides, and 2H-azirines can be easily produced.
Short alkyl chain Heck (type) reactions, especially methyl Heck reactions, are a difficult aspect of the alkyl Heck reaction. To provide a solution to this problem, iron-catalyzed methyl, ethyl and ...propyl Heck reactions were developed using readily available alkyl peroxides as alkyl sources. The reaction conditions were mild, clean, and easy to handle. No additive was needed, and no hazardous waste was generated. The products were obtained in up to 99% yield of one isomer for most situations. This reaction works for many types of olefin and tolerates a variety of functional groups. Several late-stage functionalizations of natural products and drug molecules were conducted to demonstrate the synthetic applications of this reaction.
The straightforward strategy of building a chiral C-O bond directly on a general carbon radical center is challenging and stereocontrol of the reactions of open-chain hydrocarbon radicals remains a ...largely unsolved problem. Advance in this elementary step will spur the development of asymmetric radical C-O bond construction. Herein, we report a copper-catalyzed regioselective and enantioselective carboesterification of substituted dienes using alkyl diacyl peroxides as the source of both the carbon and oxygen substituents. The participation of external acids in this reaction substantially extends its applicability and leads to structurally diverse allylic ester products. This work represents the advance in the key elementary reaction of intermolecular enantioselective construction of C-O bond on open-chain hydrocarbon radicals and may lead to the discovery of other asymmetric radical reactions.
Organofluorine compounds have shown their great value in many aspects. Moreover, allenes are also a class of important compounds. Fluorinated or fluoroalkylated allenes might provide an option as ...candidates for drug and material developments, as allenes allow a great number of valuable transformations. Herein, we report a metal-free synthesis of difluoromethylated allenes via regioselective trifunctionalization of 1,3-enynes. This method proceeds through double C-F bond formation with concomitant introduction of an amino group to the allene. Synthetic applications are conducted and preliminary mechanistic studies suggest that a two-step pathway is involved. DFT calculations revealed an unusual dibenzenesulfonimide-assisted fluorination/fluoroamination with NFSI. In addition, kinetic reaction study revealed the induction period of both major and side products to support the proposed reaction mechanism. This work offers a convenient approach for the synthesis of a range of difluoromethylated allenes and is also a rare example of trifunctionalization of 1,3-enynes.
A copper‐catalyzed asymmetric cyano(fluoro)alkylation reaction of alkenes is reported. A range of chiral fluoroalkyl cyanides were obtained in high yields and excellent enantiomeric excess from ...readily available chemicals. The method uses fluoroalkyl iodides as the fluoroalkyl source and employs mild conditions. The peroxide LPO plays a significant role in promotion of this radical asymmetric reaction.
A decarboxylative alkyl esterification of vinylarenes induced by visible light is described. A variety of alkyl diacyl peroxides synthesized from readily available aliphatic carboxylic acids are used ...as not only the oxygenation but also alkylation source. This simple and easy to handle reaction has a wide substrate scope, excellent yields, and works under mild reaction conditions. Carbon dioxide is the sole byproduct. An oxidative quenching process is proposed as the mechanism.
Shine On! A mild and redox‐neutral method for the decarboxylative alkyl esterification of vinylarenes induced by visible light is described. A variety of alkyl diacyl peroxides synthesized from readily available aliphatic carboxylic acids act as both the alkylation and oxygenation source. This simple and easy to handle reaction has a wide substrate scope, excellent yields, and works under mild reaction conditions with carbon dioxide as the sole byproduct.
Asymmetric aminoazidation and diazidation of alkenes are straightforward strategies to build value‐added chiral nitrogen‐containing compounds from feedstock chemicals. They provide direct access to ...chiral organoazides and complement enantioselective diamination. Despite the advances in non‐asymmetric reactions, asymmetric aminoazidation or diazidation based on acyclic systems has not been previously reported. Here we describe the iron‐catalyzed intermolecular asymmetric aminoazidation and diazidation of styrenes. The method is practically useful and requires relatively low loading of catalyst and chiral ligand. With mild reaction conditions, the reaction can be completed on a 20 mmol scale. Studies of the mechanism suggest that the reaction proceeds via a radical pathway and involves stereocontrol of an acyclic free radical which probably takes place through a group transfer mechanism.
Biologically accessible hydroxylation in nature often proceeds through a radical rebound process. However, such a radical rebound usually leads to non‐stereoselectivity. Rendering the radical rebound enantioselective is quite challenging. Herein, the first radical asymmetric aminoazidation and diazidation on acyclic systems via radical rebound is reported.
A copper‐catalyzed decarboxylative alkylation of terminal alkynes under mild reaction conditions has been reported. Various alkyl diacyl peroxides were applied as the alkyl source for the formation ...of C(sp3)−C(sp) bond. A range of terminal alkynes including aryl alkynes and alkyl alkynes delivered the alkylated internal alkynes with good to high performances. Mechanism studies suggested that this reaction involves a free radical pathway.
The carbon-nitrogen bond is one of the most prevalent chemical bonds in natural and artificial molecules, as many naturally existing organic molecules, pharmaceuticals, agrochemicals, and functional ...materials contain at least one nitrogen atom. Radical decarboxylative carbon-nitrogen bond formation from readily available carboxylic acids and their derivatives has emerged as an attractive and valuable tool in modern synthetic chemistry. The promising achievements in this research topic have been demonstrated via utilizing this strategy in the synthesis of complex natural products. In this review, we will cover carbon-nitrogen bond formation via radical decarboxylation of carboxylic acids, Barton esters, MPDOC esters,
-hydroxyphthalimide esters (NHP esters), oxime esters, aryliodine(III) dicarboxylates, and others, respectively. This review aims to bring readers a comprehensive survey of the development in this rapidly expanding field. We hope that this review will emphasize the knowledge, highlight the proposed mechanisms, and further disclose the fascinating features in modern synthetic applications.
The enantioselective allylic amination of unactivated terminal olefins represents a direct and attractive strategy for the synthesis of enantioenriched amines. We have developed the first use of a ...nitrogen-containing reagent and a chiral palladium catalyst to convert unfunctionalized olefins into enantioenriched allylic amines via an ene reaction/2,3-rearrangement.
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