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 showed 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.

A NEW SYNTHESIS OF SULFONES VIA THE ZINC—ASSISTED COUPLING OF ARENESULFONYL CHLORIDE WITH ALKYL HALIDES

Arenesulfonyl chloride undergoes a facile one-pot coupling reaction with active halides assisted by zinc to give the corresponding sulfones in acceptable yields.

REGIOSELECTIVE O-ALKYLATION OF MYO-INOSITOL DERIV ATIVES WITH ALKYL HALIDES UNDER S-L PHASE TRANSFER CATALYTIC CONDITIONS

A convenient synthetic approach leading to protected inositol was described based on regioselective O-alkylation using alkyl halide under solid-liquid PTC condition

REACTIONS OF ORGANODILITHIUM COMPOUND WITH ALKYL HALIDES

The mechanism of the electron transfer reaction of 1,4-dilithio- tetraphenyl-1,3-butadiene with methyl iodide was studied.

Nickel-catalyzed umpolung C-S radical reductive cross coupling of S-(trifluoromethyl)arylsulfonothioates with alkyl halides

A new cooperative nickel reductive catalysis and N,N-dimethylformamide-mediated strategy for umpolung C–S radical reductive cross coupling of S-(trifluoromethyl)arylsulfonothioates with alkyl halides to produce alkyl aryl thioethers is described. This reaction features excellent selectivity, wide functionality tolerance, broad substrate scope, and facile late-stage modification of biologically relevant molecules.Mechanistic studies recognize initial generation of an amidyl radical anion via thermoinduced reduction of DMF with Sn, followed by umpolung reduction and single electron transfer of the nucleophilic sulfonyl moiety to form a sulphydryl radical and engage the Ni^(0)/Ni^(Ⅰ)/Ni^(Ⅲ)/Ni^(I) catalytic cycle.

C-H…X-C bonds in alkyl halides drive reverse selectivities in confined spaces

Binding of non-activated alkyl halides(2-20)in water-soluble cavitand(1)through supramolecular forces is here reported,with emphasis on the role of size and polarizability of the halogen atom in the formation of intramolecular C-H hydrogen bonds in confined spaces.Rare reverse affinity in water(RI<RBr<RCl)is surprisingly observed for the more water-soluble short alkyl halides in dynamic open-ended containers.Competitive bindings and theoretical calculations confirm the unusual selectivity and the presence of C-H hydrogen bonds in non-activated systems for the first time,pointing out the importance and effect of subtle forces on molecular recognition in confined spaces.

Immobilization of HX:[Hmim]X as Halogenating Agent, Recyclable Catalyst and Medium for Conversion of Alcohols to Alkyl Halides

HX is immobilized by reaction of halogen acid with methylimidazole, and the formed ionic liquid [Hmim]X was used as halogenating agent, catalyst as well as medium for conversion of alcohols to alkyl halides. Excellent yields were obtained. The halides produced could be easily separated from the reaction mixture via simple decantation, and the ionic liquid [Hmim]X could be regenerated conveniently by adding equivalent of halogen acids followed by removal of water.

A novel and efficient synthesis of alkyl thiocyanates from alkyl halides in water using phase transfer catalysts

1,4-Bis（triphenylphosphonium）-2-butene dichloride（BTPBDC） and 1,4-bis（triphenyl phosphonium）-2-butene dithiocyanate （BTPBDT） were prepared and used as phase-transfer catalysts.Alkyl halides were converted efficiently to the corresponding alkyl thiocyanates under mild reaction conditions in water.No evidence for the formation of isothiocyanates as by-product of the reaction was observed.

An Efficient and Novel Synthesis of Carbamate Esters from the Coupling of Amines, Halides and Carbon Dioxide in the Presence of Basic Resin

A convenient, efficient, one-pot, novel process has been developed for the synthesis of carbamates from corresponding alkyl halides and amines using basic resin/CO2 system.

A facile and convenient method for synthesis of alkyl thiocyanates under homogeneous phase transfer catalyst conditions

A simple and environmentally friendly method is described for the efficient conversion of alkyl halide to alkyl thiocyanate using tetrabutylammonium bromide （TBAB） as a phase transfer catalyst. The reactions occur in water and furnish the corresponding alkyl thiocyanate in high yields. No evidence for the formation of isothiocyanates as by-product of the reaction was observed and the products were obtained in pure form without further purification.

STUDY ON THE CATIONIC POLYMERIZATION OF 1, 3-PENTADIENE INITIATED BY AlCl_3/ALKYL HALIDE SYSTEMS

The cationic polymerizations of 1, 3-pentadiene were initiated by AlCl_3 in n-hexaneat 30℃ in the presence of alkyl halides, i.e., tert-butyl chloride, tert-butyl bromide andisobutyl chloride. The effects of these halides on the polymer yield, molecular weight,crosslinking reaction, cyclization and polymer microstructure, have been investigated. Twomain side reactions, crosslinking and cyclization, were suppressed and reduced by theaddition of the halides. The proportion of 1, 4 units of polymer chains was increasedby the presence of the halides, which reduced the polymer yield and the molecular weightof polymers.

A Novel Method of Preparing Unsymmetrical Thioether from Disulfides

The disulfides reacted with zinc in DMF, followed by alkyl halides, giving unsymmetrical thioether in excellent yields. This reaction takes place under mild and neutral conditions.

In situ Ionothermal Synthesis and Characterization of a Novel Cuprous Halide Complex

A new compound [mpba][Cu_2Br_3]（1, mpba = 4-（N-methylpyridin-4-yl）benzoic acid） has been ionothermally synthesized and characterized by single-crystal X-ray diffraction analysis, infrared spectrum, elemental analyses, fluorescence spectrum, and thermogravimetric analysis. In compound 1, the [mpba]＋ cation is a new organic template, which is obtained firstly in this work by in situ alkylation reaction of N-heterocycles 4-（pyridin-4-yl）benzoic acid with [Emim]Br（Emim = 1-ethyl-3-methyl imidazolium）. Hirshfeld surface analysis shows that weak interactions between the [mpba]＋ cations and 1D inorganic [Cu_2Br_3]~– are mainly C–H···Br hydrogen bonds. In addition, a pairwise O–H···O interaction is observed between the adjacent [mpba]＋cations. These different types of weak interactions make compound 1 stable up to 300 ℃. Fluorescence spectrum investigation shows 1 has a strong yellow emission at 555 nm. Theoretical calculation not only demonstrates compound 1 is a wild band semiconductor with a 3.3 e V band gap but also elucidates the fluorescence emission derives from the p-π＊ transition of electrons from [Cu_2Br_3]~– to [mpba]~＋.

Elimination of HBr from CH_3Br by Cu^+ and Au^+:A DFT study

The elimination of HBr from CH3Br by ground state of Cu＋ and Au＋ has been investigated by using DFT methods. A mechanism of one-step HBr elimination leading to CuCH2＋ was identified. For the formation of AuCH2＋, besides the one-step mechanism, another two-step HBr elimination pathway through a C-Br bond insertion intermediate was also found, and this pathway is energetically more favorable than the one-step mechanism. The calculated reaction energy barriers show that the formation of AuCH2＋ is energetically much more favorable than the formation of CuCH2＋. The experimental observations are well explained.

Radical Arbuzov Reaction

The Arbuzov reaction(also known as the Michaelis–Arbuzov reaction)is one of the most fundamental transformations in organic chemistry and has been extensively used for the synthesis of organophosphorus compounds for over a century.However,the reaction generally requires an elevated temperature and is applicable mainly to primary alkyl halides with poor functional group tolerance.We report herein a radical alternative to the conventional nucleophilic substitution reaction.Thus,new radical phosphonylation reagents,9-fluorenyl o-phenylene phosphite and benzhydryl o-phenylene phosphite,have been developed for this purpose.The photoredox-catalyzed reaction of a wide range of alkyl bromides or iodides with 9-fluorenyl(or benzhydryl)o-phenylene phosphite followed by workup with methanol(or ethanol)provides the corresponding dimethyl(or diethyl)alkylphosphonates in satisfactory yields at room temperature under mild conditions.The method is applicable to primary,secondary,and even tertiary alkyl iodides and bromides and exhibits an excellent functional group tolerance,thereby enabling the late-stage modification of complex molecules and rapid synthesis of phosphonate-containing natural products and drug molecules.A mechanism involving the formation and subsequentβ-scission of phosphoranyl radicals is proposed.

Nucleophilic Trifluoromethylthiolation of Alkyl Chlorides, Bromides and Tosylates

A direct nucleophilic trifluoromethylthiolation of alkyl chlorides, bromides and tosylates with AgSCF3 was de- scribed. It was found that the presence of nBu4NI or a combination of nBu4NI/nBu4NBr significantly enhanced the reaction rates. The reaction conditions were mild, thus allowing the tolerance of a variety of functional groups.

Reductive Cleavage of the Te-Te Bond in Diphenyl Ditelluride by the Sm/CrCl_3(cat.) System: Preparation of Telluroesters and Unsymmetrical Phenyltellurides

The reduction of diphenyl ditelluride by the Sm/CrCl_3(cat.) system led to atelluride anion. This species reacted with acid chlorides, alkyl halides, and α,β-unsaturatedenoates or α,β-unsaturated ene nitriles to afford telluroesters and unsymniet-ricalphenyltellurides, respectively, in moderate to good yields under mild and neutral conditions.

Expedient copper-catalyzed borylation reactions using amino acids as ligands

Amino acids were found to be as good ligands for copper-catalyzed borylation reactions of primary and secondary alkyl halides,and the B2pin2 acted as bi-boron source for borylation.The high reaction efficiency and mild conditions make the new catalyst system a useful alternative to the recently developed methods for the preparation of alkylboronic esters.