C- and O-Alkylation with α-Haloketones of the Adamantane Series

Reactions of 1-adamantyl bromomethyl ketone and 1-(1-adamantyl)-3-bromo-2-propanone with acetylacetone and ethyl acetoacetate in a mixture of dry diethyl ether with anhydrous methanol in the presence of sodium methoxide afforded 3-(1-adamantylcarbonylmethyl)-2,4-pentanedione, ethyl 2-(1-adamantylcarbonylmethyl)-3-oxobutanoate, 4-acetyl-1-(1-adamantyl)-2,5-hexanedione, and ethyl 2-acetyl-5-(1-adamantyl)-4-oxopentanoate. The Knoevenagel-Cope reactions of 1-adamantyl bromomethyl ketone and 1-(1-adamantyl)-3-bromo-2-propanone with diethyl malonate yielded, respectively, diethyl 1-(1-adamantyl)-2-bromoethylidenemalonate and diethyl 1-(1-adamantylmethyl)-2-bromoethylidenemalonate. O-Alkylation of ethyl acetoacetate with 1-adamantyl bromomethyl ketone gave ethyl 3-(1-adamantylcarbonylmethoxy)-2-butenoate. Carboxylic acids reacted with 1-adamantyl bromomethyl ketone to form the corresponding 2-(1-adamantyl)-2-oxoethyl carboxylates.     

Sodium Formaldehyde Sulphoxylate an Efficient Reagent For The Reduction of α-Haloketones

Sodium formaldehyde sulphoxylate is shown to be an inexpensive, efficient reagent for the dehalogenation of phenacyl halides and other α-haloketones. Some possible mechanisms for the reduction are discussed.     

Ligand-Controlled Palladium-Catalyzed Carbonylation of Alkynols: Highly Selective Synthesis of α-Methylene-β-Lactones

The first general and regioselective Pd-catalyzed cyclocarbonylation to give α-methylene-β-lactones is reported. Key to the success for this process is the use of a specific sterically demanding phosphine ligand based on N-arylated imidazole ( L11 ) in the presence of Pd(MeCN)₂Cl₂ as pre-catalyst. A variety of easily available alkynols provide under additive-free conditions the corresponding α-methylene-β-lactones in moderate to good yields with excellent regio- and diastereoselectivity. The applicability of this novel methodology is showcased by the direct carbonylation of biologically active molecules including natural products.     

Synthesis of 1,3-Diketones by Reaction of α-Haloketones with Acyl Cyanides Promoted by Samarium Diiodide

α-Haloketones reacted with acyl cyanides to form 1,3-diketones in the presence of samarium diiodide. The reaction was assumed to proceed via a mechanism involving samarium enolates formed in situ from α-haloketones.     

Facile Synthesis of α-Haloketones by Aerobic Oxidation of Olefins Using KX as Nonhazardous Halogen Source

Summary of main observation and conclusion An operationally simple and safe synthesis of a-haloketones using KBr and KCI as nonhazardous halogen sources is reported.It involves an iron-catalysed reaction of alkenes with KBr/KCl using O2 as terminal oxidant under the irradiation of visible-light.This strategy avoids the risks associated with handling halo-contained electrophiles(Cl2,Br2/NCS,NBS).The process is tolerant to several functional groups,and extended to a range of substituted styrenes in up to 89%yield.A radical reaction pathway is proposed based on control experiments and spectroscopy studies.     

Hydro-Dehalogenation of α-Haloketones by Tin (II) Chloride and Sodium Hydrogen Sulfide

Aromatic and aliphatic α-haloketones were effectively dehalogenated by binary systems of sodium hydrogen sulfide (soft base) and a metal chloride such as tin (II) chloride, iron (II) chloride or chromium (III) chloride (hard acid).     

The Reaction of Thioacids with α-Haloketones in Water: an Environmentally Green Synthesis of Thioester Derivatives

Abstract

The reaction between a thioacid and an α-haloketone in water affords thioester derivatives in high yields. The reaction proceeded smoothly and cleanly under mild conditions and no side reactions were observed.     

Reaction of α-Haloketones with ortho-Dihydroxy-2H-1-benzopyran-2-ones. Formation of α-Pyrano-1,5-benzodioxapines-A New Heterocyclic System

Reaction of 7,8-dihydroxy-2H-1-benzopyran-2-one, and its 4-methyl derivative, with α-haloketones affords α-pyrano-1,5-benzodioxapines, while 3-chloro-4-methyl-7,8-dihydroxy-2H-1-benzopyran-2-one gives α-pyrano-1,4-benzodioxane. The structures of the compounds were deduced using a combination of ¹H nmr, ¹³C nmr (BB, DEPT), HETCOR, NOESY, and selective INEPT techniques and molecular modeling.     

Sodium Percarbonate: A Convenient Reagent for the Thermal and Sonic Oxidative Cleavage of α-Haloketones

Sodium percarbonate has been found to be a mild and effective reagent for the oxidative cleavage of α-haloketones to carboxylic acids. Furthermore, the reactions are dramatically accelerated in the presence of ultrasound with significant enhancement in yields.     

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.     

β-Diketone Synthesis by Reaction of α-Haloketones with Acid Chlorides or Acid Anhydrides Promoted by Samarium Triiodide

Promoted by SmI₃, α-haloketones were reacted with acid chlorides or acid anhydrides and β-diketones were synthesized via intermediate samarium enolates.     

Synthesis of Benzoxazolinone by Selenium-Catalyzed Carbonylation with Carbon Monoxide

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N-Heterocyclic Carbene-Palladium Complex Catalyzed Oxidative Carbonylation of Amines to Ureas

Palladium carbene shows high efficiency without any promoter on oxidative carbonylation of amines to ureas and a new type of palladium carbene complex containing both an aniline and an NHC ligands was found to be the active species for the reaction.     

Kinetics of Methanol Carbonylation to Methyl Formate Catalyzed by Sodium Methoxide

Kinetics of synthesis of methyl formate from carbon monoxide and methanol, using sodium methoxide as the catalyst and pyridine as the promoter in a batch reactor, was studied. Kinetic parameters such as the apparent reaction orders, the rate constant and the apparent activation energies were obtained. The experimental results showed that both the reaction orders with respect to CO and methanol equal to 1, the general reaction kinetic equation is (-r)=-dp(CO)/dt=k, p(CO).[MeOH], and the rate constant is k=8.82×10~6exp [-61.19×10~3/(R·T)] in the presence of pyridine. The apparent activation energies had decreased 6.44 kJ/mol and the rate constant had increased more than 1.5 times when pyridine was used as the promoter in the catalyst system.     

Efficient Synthesis of Polycyclic γ-Lactams by Catalytic Carbonylation of Ene-Imines via Nickelacycle Intermediates

The nickel(0)-catalyzed carbonylative cycloaddition of 1,5- and 1,6-ene-imines with carbon monoxide (CO) is reported. Key to this reaction is the efficient regeneration of the catalytically active nickel(0) species from nickel carbonyl complexes such as [Ni(CO)₃L]. A variety of tri- and tetracyclic γ-lactams were thus prepared in excellent yields with 100 % atom efficiency. Preliminary results on asymmetric derivatives promise potential in the synthesis of enantioenriched polycyclic γ-lactams.     

Study on the Synthesis of Phenylacetic Acid by Carbonylation of Benzyl Chloride under Normal Pressure

The influences of some factors on the yield of phenylacetic acid in the carbonylation of benzyl chloride were studied in this paper. These factors included the variety and content of catalyst, and that of solvent, way of material feeding, reaction temperature, sodium hydrate concentration, triphenylphosphine content, presence of surfactant, the ratio of organic phase volume to aqueous phase volume etc. The optimum reaction conditions were found to be: with a one-time pour of 0.15g Pd(PPh3)2Cl2, 0.24g PPh3, 75ml NaOH of 3.5mol/L, 20ml benzyl chloride and 55ml n-butyl alcohol, and the reaction was carried out at 50℃ for about 3 hours. The as-obtained yield of phenylacetic acid was as high as 97.6%. In addition, the influences of the presence of phenylacetic acid and air in the reaction system were also studied. The results showed that the presence of air in the system and the entrainment of phenylacetic acid in the circulating organic phase had great influence on the reaction rate, the stability and performance of catalyst and the yield of phenylacetic acid.     

Amine-Responsive Disassembly of AuI–CuI Double Salts for Oxidative Carbonylation

A sensitive amine-responsive disassembly of self-assembled Au^I-Cu^I double salts was observed and its utilization for the synergistic catalysis was enlightened. Investigation of the disassembly of [Au(NHC)₂][CuI₂] revealed the contribution of Cu-assisted ligand exchange of N-heterocyclic carbene (NHC) by amine in [Au(NHC)₂]⁺ and the capacity of [CuI₂]⁻ on the oxidative step. By integrating the implicative information coded in the responsive behavior and inherent catalytic functions of d¹⁰ metal complexes, a catalyst for the oxidative carbonylation of amines was developed. The advantages of this method were clearly reflected on mild reaction conditions and the significantly expanded scope (51 examples); both primary and steric secondary amines can be employed as substrates. The cooperative reactivity from Au and Cu centers, as an indispensable prerequisite for the excellent catalytic performance, was validated in the synthesis of (un)symmetric ureas and carbamates.     

The Activation and Carbonylation of the C-Cl Bond Catalyzed by Transition-Metal Complexes

Thecarbonylationoforganichalides,catalyzedbytransition-metalcomPlexes,isareactionofindustrialinterestleadingtoawiderange0fproductslilieesters,aldehydes,awhdesandacids.Formanyyears,catalyticactivationandfunctionalisationofthecarbonthalogenbondsinorganichalideshavebeenoneofthemostchallengingproblemsanddesirablegoalsforchendsts.Oforganichalides,0rgancchlorideisthemodrmaforeundiDexPdrieerefD1thepeDfu3efulboinboLalindusny.However,because0ftheinertness0ftheirC-Clbonds,organicchloridesexhibitl0wre…