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1.
A palladium-catalyzed 1,4-enyne synthesis was developed based the decarboxylative coupling of acetylides with allyl electrophiles. Stereochemical studies have implicated palladium-allyl-acetylides as intermediates. Thus, decarboxylative metalation was established as an environmentally benign alternative to transmetalation from alkynyl tin reagents.  相似文献   

2.
A Br?nsted acid-catalyzed decarboxylative redox amination involving aldehydes with 2-carboxyindoline for the synthesis of N-alkylindoles is described. The decarboxylative condensations of aldehydes with 2-carboxyindoline produce azomethine ylides in situ, which then transform into N-alkylindoles by isomerization.  相似文献   

3.
As a result of the low reactivity of simple esters, the use of them as nucleophiles in direct asymmetric transformations is a long-standing challenge in synthetic organic chemistry. Nature approaches this difficulty through a decarboxylative mechanism, which is used for polyketide synthesis. Inspired by nature, we report guanidine-catalyzed biomimetic decarboxylative C-C and C-N bond-formation reactions. These highly enantioselective decarboxylative Mannich and amination reactions utilized malonic acid half thioesters as simple ester surrogates. It is proposed that nucleophilic addition precedes decarboxylation in the mechanism, which has been investigated in detail through the identification of intermediates by using electrospray ionization (ESI) mass-spectrometric analysis and DFT calculations.  相似文献   

4.
(5 )-Prostaglandin E2 (7) was synthesized fron ( )-4- -butyldimethylsilyloxy-2-cyclopentenone (1) by 2-alkenyloxycarbonylatlon of the organocopper conjugate-addition adduct (3) followed by intramolecular palladium-catalyzed decarboxylative allylic alkylation. The (5 )-prostaglandin E2 skeleton was also obtained from the β-keto allylic ester (11) by a similar decarboxylative allylic alkylation. The decarboxylative allylic alkylation of another type of the three-component coupling product (12) gave new 6-methyleneprostaglandin E1 skeleton (15a), which was converted into new 6-methylprosta-glandin I methyl ester (20) 6-methyleneprostaglandin F1 derivative (16) by two different ways. The stereochemistry of this intramolecular decarboxylative allylic alkylation was discussed in the reaction of 2-[( )- or ( )-2-butenyloxy-carbonyl] cyclopentanone systems.  相似文献   

5.
Herein, unprecedented rhenium‐catalyzed decarboxylative oxytri‐/difluoromethylation and Heck‐type trifluoromethylation of styrenes have been developed by using hypervalent iodine(III) reagents derived from cheap, stable, and easy‐handling fluorinated carboxylic acids. Mechanistic studies revealed a radical decarboxylative trifluoromethylation pathway occurring in these reactions.  相似文献   

6.
Wang C  Tunge JA 《Organic letters》2006,8(15):3211-3214
[Structure: see text] 6-Vinyl oxazinanones undergo catalytic, diastereoselective, decarboxylative ring contraction to form vinyl azetidines in good yield. Performing the decarboxylation in the presence of Michael acceptors results in decarboxylative olefin insertion to provide diastereoenriched substituted vinyl piperidines.  相似文献   

7.
Protected homoallylic amines are synthesized by the decarboxylative coupling of alpha-amino acid derivatives. The catalytic C-C bond-forming reaction relies on the bioinspired decarboxylative metalation of alpha-amino acids to produce alpha-amino anion equivalents. The alpha-amino anion equivalents are intercepted by pi-allyl palladium electrophiles to produce substituted homoallylic amines.  相似文献   

8.
A copper-catalyzed decarboxylative cross-coupling reaction of propiolic acids with terminal alkynes is developed leading to unsymmetric 1,3-conjugated diynes under mild conditions. This method provides a novel decarboxylative cross-coupling for sp-sp bond formation. Compared to organic halides, only carbon dioxide is produced as by-products in this approach.  相似文献   

9.
The reaction of α-benzenesulfonylphenylacetic acid with some alkyl halides, using as base NaH in DMSO, leads to decarboxylative protonation to give benzylphenylsulfone. Decarboxylative alkylation occurs only when CO2 is expelled by flushing with nitrogen. The mechanism of the decarboxylative protonation is investigated.  相似文献   

10.
Decarboxylative benzylation of nitriles is achieved via coupling of metallated nitriles with Pd-π-benzyl complexes that are generated in situ from cyanoacetic benzyl esters. In addition, decarboxylative couplings of α,α-disubstituted 2-methylfuranyl cyanoacetates can lead to either decarboxylative arylation or benzylation depending on the reaction conditions.  相似文献   

11.
Ruthenium(II) bis(carboxylate)s proved highly effective for two decarboxylative C−H alkenylation strategies. The decarboxylation proceeded efficiently at rather low temperatures. The unique versatility of the decarboxylative ruthenium(II) catalysis is reflected in the oxidative olefinations with alkenes as well as the redox‐neutral hydroarylations of alkynes.  相似文献   

12.
A new catalyst system, generated in situ from Cu2O, 1,10-phenanthroline, PdI2, and Tol-BINAP, for the first time allows the decarboxylative coupling of carboxylic acids with aryl triflates. In contrast to previous decarboxylative couplings that remained limited to certain activated carboxylates, e.g., ortho-substituted benzoates, this halide-free protocol is generally applicable to aromatic carboxylic acid salts regardless of their substitution pattern.  相似文献   

13.
An enantiospecific palladium‐catalyzed decarboxylative coupling of acyclic β,γ‐alkynoic acids with various aryl iodides to chiral tetrasubstituted allenes is described. The coupling reaction comprises a decarboxylative γ‐palladation of α,α‐disubstituted carboxylic acids to provide the tetrasubstituted allenes with complete point‐to‐axial chirality transfer in excellent yields.  相似文献   

14.
A stereospecific decarboxylative silylation of acrylic and propiolic acids with silanes was developed. This reaction represents the first example of decarboxylative C? Si bond formation and provides an efficient and convenient approach to various synthetically useful alkenyl and alkynyl organosilicon compounds through the reaction of α,β‐unsaturated acids with silanes. Spin‐trapping and EPR experiments support a radical addition/elimination process.  相似文献   

15.
A simple route to diaryl sulfides using a decarboxylative palladium-catalyzed reaction between electron-rich 2,6-dialkoxybenzoic acid derivatives and diaryl disulfides is reported. This coupling proceeds efficiently in the presence of Pd(CF(3)CO(2))(2) and Ag(2)CO(3) in a 65:1 mixture of 1,4-dioxane and tetramethylene sulfoxide (TMSO). We present also the first formation of a carbon-selenium bond via a palladium-catalyzed decarboxylative cross-coupling.  相似文献   

16.
H Wang  LN Guo  XH Duan 《Organic letters》2012,14(17):4358-4361
An efficient catalytic decarboxylative acylation of unactivated sp(2) (alkenyl) C-H bonds has been developed. Various substituted α-oxocarboxylic acids with different electronic properties react under mild conditions to afford a diverse range of β-acyl enamide products in good yields. The reaction is proposed to proceed via a cyclic vinylpalladium intermediate, facilitating the decarboxylative dehydrogenative process with enamide coupling partners.  相似文献   

17.
A visible light‐induced decarboxylative alkylation of heterocyclic aromatics with aliphatic carboxylic acids was developed by using anthocyanins as a photocatalyst under mild conditions. A series of alkylated heterocyclic compounds were obtained in moderate to good yields by using the metal‐free decarboxylative coupling reaction under blue light. This strategy uses cheap and readily available carboxylic acids as alkylation reagents with good functional group tolerance and environmental friendliness. It is worth noting that this is the first time that anthocyanin has been used to catalyze the Minisci‐type C?H alkylation. The mechanism of decarboxylation alkylation was studied by capturing the adduct of alkyl radical and hydroquinone, thus confirming a radical mechanism. This protocol provides an alternative visible light‐induced decarboxylative alkylation for the functionalization of heterocyclic aromatics.  相似文献   

18.
A photoinduced decarboxylative three-component coupling reaction involving amine, maleic anhydride, and fluorinated alkyl iodides has been developed, leading to synthetically valuable fluoroalkyl-containing acrylamides with a high E selectivity. A broad array of substrates including monoprotected amino acid are capable coupling partners. Preliminary mechanistic studies suggest a stepwise process. This reaction represents the first example of photoinduced decarboxylative difunctionalization of maleic anhydride.  相似文献   

19.
Visible‐light‐induced photocatalytic decarboxylative alkynylations of carboxylic acids have been developed for the first time. The reaction features extremely mild conditions, broad substrate scope, and avoids additional oxidants. Importantly, a decarboxylative carbonylative alkynylation has also been carried out in the presence of carbon monoxide (CO) under photocatalytic conditions, which affords valuable ynones in high yields at room temperature.  相似文献   

20.
Most alkynes are volatile liquids, which are relatively difficult to use and to transport. In contrast, alkynyl carboxylic acids offer a stable and attractive alternative for the alkynylation reactions. Here, we employed alkynyl carboxylic acids as reaction partners for the alkynylation of aryl halides. Copper-catalyzed decarboxylative coupling, including various challenging aryl bromides with phenylpropiolic acid, was performed in water without using co-solvents with good yields. Our approach provides a low-loading, low-cost, stable and environmentally friendly copper catalyst system for decarboxylative coupling.  相似文献   

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