Photopromoted Carbonylation of Alkyl Halides Under Ambient Conditions

Photopromoted carbonylation of alkyl halides with carbon monoxide can be carried out under ambient conditions with non-precious transition metal complexes(such as cobalt complexes) catalysts.Our preliminary work sowed that alkyl halides can be transformed into alkene and alkane directly under irradiation,but the esters can not be transformed.It is assumed that the carbonylation of alkyl halides may be proceeded in two ways.     

Synthesis of α-Arylated Esters from Aryl Halides

The preparation of α-arylalkanoic acid esters has received significant attention, not only due to these compounds are important industrial materials, but also some of them are nonsteroidal anti-inflammatory drugs (NSAID)1. Arylation of β-dicarbonyl carb…     

The Sulfinatodehalogenation Reaction of α,α-Difluorobenzyl Halides with Sodium Dithionite

Since the discovery of the first sulfinatodehalogenation reaction in 1981 1, great efforts havebeen devoted to this useful reaction. The substrates have been expanded fromperfluoroalkyl iodide (R.I) to per- and poly-fluoroalkyl handes (R,X, X = Br, I, R,CCI,),and many sulfinatodehalogenating reagents such as NaZSZO4, HOCH,SO,Na,H,NC(=NH)SO,H and NaZSZO, have been developed=. Recently, thesulfinatodehalogenation of 2,2,2-trifluoroethyl handes was accomplished by Chen et al.'Howev…     

The Reactions Between Halides and Alcohols in the Presence of Phase Transfer

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The Sulfinatodehalogenation Reaction of α ,α -Difluorobenzyl Halides with Sodium Dithionite

The sulfinatodehalogenation reaction of α,α-difluorobenzyl halides, ArCF2X ( Ar = C6F5, C6H5; X = Br, I ), with sodium dithionite took place readily in aqueous acetonitrile under mild conditions, giving the corresponding sodium sulfinate. The 1:1 adducts were obtained when alkenes were added to the reaction system in some cases.     

Ionic Hydrogenation of α,β-Unsaturated Ketones with Cyclohexane in the Presence of Aluminum Halides

4-Methyl-3-penten-2-one, 3-hepten-2-one, 3-methyl-1-phenyl-2-buten-1-one, 4-(2,4-dichlorophenyl)-, 4-(4-hydroxyphenyl)-, 4-(4-methoxyphenyl)-, 4-(2-hydroxyphenyl)-, and 4-(4-dimethylaminophenyl)-3-buten-2-ones, and 3-(4-methoxyphenyl)-1-phenyl-2-propenone react with cyclohexane in the presence of excess aluminum chloride or aluminum bromide in CH2Cl2 or CH2Br2, respectively, at room temperature to form the corresponding saturated ketones in high yields. Using 4-phenyl- and 4-(4-methoxyphenyl)-3-buten-2-ones as examples, it was shown that the reaction pattern does not change in going from the Lewis acids AlCl3 and AlBr3 to proton-donor acid system CF₃SO₃H-SbF₅. The reactive intermediates are likely to be C-protonated complexes of ,-unsaturated ketones with aluminum halides or their O,C-diprotonated analogs.     

Asymmetric Synthesis of Chiral-at-P Alkenylphosphonamidates through Nickel-Catalyzed C−P Coupling of Phosphoramidites and Alkenyl Halides

P-stereogenic compounds are widely used as ligands in asymmetric catalysis and are present in a myriad of bioactive compounds and pharmaceuticals. Yet, their stereocontrolled preparation remains challenging. Herein, we report a novel strategy towards versatile chiral-at-P alkenylphosphonamidates through a one-pot Ni-catalyzed C−P coupling/diastereoselective hydrolysis of readily available phosphoramidites and alkenyl halides. Remarkably, a chemo- and diastereodivergent behavior was observed upon subtle changes in the reaction conditions. Additionally, selective derivatizations of chiral alkenylphosphonamidates demonstrate their versatility as building blocks for the synthesis of structurally diverse P-stereogenic compounds.     

Cobalt（I） Catalyzed Reaction of Benzaldehydes with Functionalized Benzylic Zinc Halides

Functionalized benzylic zinc halides reacted with benzaldehydes in the presence of Lewis acid Me3SiCl giving high yields of trans-stibenes under the catalysis of Co(PPh3)3Cl.     

Copper-Catalyzed Regioselective Borocarbonylative Coupling of Unactivated Alkenes with Alkyl Halides: Synthesis of β-Boryl Ketones

The borocarbonylative coupling of unactivated alkenes with alkyl halides remains a challenge. In this communication, a Cu-catalyzed borocarbonylative coupling of unactivated alkenes with alkyl halides for the synthesis of β-boryl ketones has been developed. A broad range of β-boryl ketone derivatives was prepared in moderate to excellent yields with complete regioselectivity.     

Dehalogenation of Aryl Halides Catalyzed by Montmorillonite Immobilized Bimetal Catalyst in Aqueous System

A novel bisupported bimetal catalyst PVP-PdCl2-FeSO4/Al-Mont-PEG600 was prepared by immobilization of PVP (poly (N-vinyl-2-pyrrolidone)) supported bimetallic catalyst using alumina pillared inartificial montmorillonite as the carrier. This catalyst has good dehalogenation activity and selectivity to aryl halides-o-chlorotoluene in aqueous system in the presence of phase transfer catalyst (PEG) and sodium formate as hydrogen source. The catalyst also shows good reusability.     

Substitution Reaction of Nitro Group on α-Nitrostyrene by Organozinc Halides under Microwave Irradiation

In recent years, organozinc reagents (R2Zn and RZnX) have been proved to be very useful in organic synthesis. [1] And the application of organozinc halides (RZnX) in organic synthesis has been extensively investigated.     

Theoretical Study of Reactions of α-Diimines with P(III) Acid Halides by Semiempirical Quantum-Chemical Methods

Stability of potential products of -diimine reactions with P(III) acid halides was characterized by PM3 semiempirical quantum-chemical calculations with full geometry optimization. The energetic favorability of formation of diazaphospholene (oxodiazaphospholene) or diazaphospholane cyclic structures with an exocyclic diene system from acyclic diimines and cyclohexanediimine and the unfavorability of formation of similar structures from dihydropyrazines was demonstrated. Dihydropyrazines should prefer phosphorylation involving one of the C = N bond. The calculation results fairly agree with available experimental data and allow prognosis of the probability of formation of one or another structure in new reactions.     

New Condensation Reaction of β-keto-δ-valerolactones, Carbon Disulfide and Alkyl Halides

β-Keto-δ-valerolactones, which were obtained by reaction of acetoacetate with aldehydes or ketones, reacted with carbon disulfide, alkyl halides and a new condensation reaction was developed. The structures of the products 3 were confirmed by ^1HNMR spectra and elemental analysis.     

Triton B–Mediated Efficient and Convenient Alkoxylation of Activated Aryl and Heteroaryl Halides

A simple and convenient one-pot synthesis of aryl alkyl ethers by the alkoxylation of aryl halides with alcohol in the presence of Triton B as a base is described. The procedure is applicable for a variety of aryl and heteroaryl halides, and yields are very good. The use of a nonmetallic base and solvent-free conditions are important features of the reaction.     

An Efficient Synthesis of Diaryl Ethers by Coupling Aryl Halides with Substituted Phenoxytrimethylsilane in the Presence of TBAF

A general synthesis of diaryl ethers via coupling of aryl halides with substituted phenoxytrimethylsilane in the presence of TBAF is described. The protocol is simple and mild, and gives good to excellent yields.     

An Efficient Synthesis of Diaryl Ethers by Coupling Aryl Halides with Substituted Phenoxytrimethylsflane in the Presence of TBAF

A general synthesis of diaryl ethers via coupling of aryl halides with substituted phenoxytrimethylsilane in the presence of TBAF is desedbed. The protocol is simple and mild,and gives good to excellent yields.     

Indium(III) Triflate–Mediated One-Step Preparation of Glycosyl Halides from Free Sugars

In(OTf)₃ has been found to be an efficient catalyst for the direct conversion of reducing sugars to their respective acylated glycosyl halides in good yields under mild conditions. The glycosyl halides so obtained can be converted to alkyl glycosides in the same pot by reacting them with the respective alcohols in good yield.     

Suzuki Coupling of Cyclopropylboronic Acid With Aryl Halides Catalyzed by a Palladium–Tetraphosphine Complex

The tetraphosphine all‐cis‐1,2,3,4‐tetrakis(diphenylphosphinomethyl)cyclopentane (Tedicyp) in combination with [Pd(C₃H₅)Cl]₂ affords a very efficient catalyst for the coupling of cyclopropylboronic acid with aryl bromides and aryl chlorides. Higher reactions rates were observed with aryl bromides than with aryl chlorides; however, even in the presence of 1–0.4% of catalyst, a few aryl chlorides gave the coupling products in good yields. A wide variety of substituents such as alkyl, methoxy, trifluoromethyl, acetyl, benzoyl, formyl, carboxylate, nitro, and nitrile on the aryl halides are tolerated. The coupling reaction of sterically very congested aryl bromides such as bromomesitylene or 2,4,6‐triisopropylbromobenzene also proceeds in good yields.     

Regioselechve Reaction of α－（Alkoxydimethylsilyl）allyl Carbanions with Alkyl Halides and Aldehydes

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β-Naphthol as a Chromophore and Fluorophore Forming Reagent in the HPLC Determination of Alkyl Halides

Abstract

A suitable chromophore- and fluorophore- forming reagent for the detection of alkyl halide water contaminants is β-naphtol. The ether derivatives are separated from each other and excess β-naphthol reagent by reverse, phase HPLC and are detected by ultraviolet absorption or fluorescence. A method for the determination of alkyl halides is presented. The method is applicable to concentration levels in the ppm range for UV detection and in the ppb concentration range using fluorescence detection.